OK, so, as a bit of scene setting in a story I am writing, a small group of people has landed on a nearly exact replica of Earth (atmospherics, geology, and physical parameters are nearly the same as Earth) and have set up a town there. Now the question I'm wondering:
Horses or Rovers? which is better for a small colony town with limited everything?
that's it
Use the local horse equivalent.
https://www.deviantart.com/louisetheanimator/art/Green-Alien-Goat-878439701
For example, the alien Giant Pygmy Goat as depicted here. You can tell it is alien because it is green. Your people were going to use rovers but the planet is loaded with alien goats who were totally up for the project. They are not as big as horses but they are really strong. The short colonists can ride just fine. Tall colonists use spurs but instead of a spike it is a castor wheel so their heels won't drag on the ground. Really tall ones might ride two goats at once. The goats are cool with all that.
Also the GGPG (giant green pygmy goats) are friendly and funny, and they give green milk which makes awesome GGPG cheese.
Your people Go with the Green Goats!
Horses' needs don't scale down very well, which would make them a liability for a small colony. A larger one could get more use out of them and better mitigate the problems.
Problem one is getting there. A spaceship is not a very good environment for a horse; they need space to run and exercise, and they need a lot of food and water which adds to your supply needs. The bigger the colony ship, the easier it is to find large open spaces for your livestock. You also need to consider what g-forces a horse can survive (I can't really imagine one being strapped into an acceleration couch...) and whether that will fit with your launch vehicle. Rovers, in contrast, pack up nicely and will handily take any g-forces your colonists will.
Problem two is that horses require a lot of specialized care and, worse, specialists that don't really overlap with your existing needs. If your rovers are electrically powered, for instance, then the batteries and motors they use run on the same principles as all the other electrical equipment in your colony. Your motor pool mechanics probably have enough know-how to swap in and fix a balky AC unit or repair a generator. On the other hand, if you keep horses, those skills are less transferable to other situations that come up. Maybe your horse handlers can keep other livestock, but that's about it. Again, in a larger population this isn't a big deal. A population of a million can afford to specialize in tons of little fields. A population of a thousand can't; each specialist is a potential pain point if that person is injured or sick.
Problem three is, where are you planning to go? A small colony doesn't really need a lot of transportation. As you describe it, they only have one town, which is presumably fairly compact. You don't need sprawling suburbs or huge factory districts. Most of the settlers' lives probably take place in easy walking distance. If your trips are fewer and further between, a rover you can park in a garage and forget about has a big advantage over a horse that still needs care and feeding whether or not you go anywhere.
As an aside, have you considered muscle power? A boat or a bicycle has far fewer moving parts than a rover, needs less maintenance than either, and is easy on your fuel supply too. And they require very little specialized know-how. They're not suited for every terrain but the nice thing about being the first colonists is, you can pretty much take your pick.
Depends on the time scale, how many people you have, and what sort of robotics you have.
A factory to build engines and produce steel and rubber and coper wire and such is a pretty big deal. Depending on your battery tech either electrical generation to charge the batteries or fossil fuel production to fuel them is also a big deal.
Horses can make more horses as soon as you let them. All you need is grass and water and simple shelter like a barn and you get more horses.
Horses do have subtantial maintenance involved, and there are some skills. Riding a horse takes some skill. Blacksmithing takes some time to learn. Making a good saddle is a significant skill. Horses must be reliably fed even in the winter. They must have reliable water supplies. They need substantial space. They must be trained and kept in training. And horses can be susceptible to a variety of health issues. So it's not automatic that they are superior.
If your colony had some honking-advanced robotic manufacturing, you might be able to tell the robots to go build a bunch of ATVs and motorcycles and SUVs and spare parts and such. Probably they can make such faster than horses could breed up enough for everybody. In this case, the powered vehicles are probably preferred.
If it's a very small colony and they don't have robotic manufacturing, probably a big factory to make vehicles would be more than they could support. In that case, probably horses would be easier, faster, and renewable.
If the "horse" is a native animal rather than a terrestrial import then the horse may be the best bet providing it has the temperament of a horse familiar to us it could be useful.
Rovers will not last as long as a population of horses. Within a few years or decades at most in rough terrain, the rovers will be dead needing spare parts (that presumably can't be manufactured in a small town). The horses will be around for millions of years.
There was a quote in a Pournelle novel, which roughly went "tractors wear out, horses make more horses." So the questions would be:
A rover needs fuel. What do you plan to use? Hydrogen, split from water by electrolysis? Keeping hydrogen in tanks can be tricky. Hydrocarbon biofuels from the fields? You need more vehicles for farming, then. Fossile fuels, if the planet has them? Start drilling ...
Tires wear out. Try to imagine what it takes for a small town to produce modern rover tires. First, you need either rubber or hydrocarbons for synthetic rubber. Different compositions for different parts. High quality if you want the tires to last. Then steel wires. Build them all up and bake them together. How much industry does that take?
Next, pick some nuts or bolts to wear out. You won't make a replacement in a village smithy, it will take a factory. With steel from a steelworks. Do you fire that with coal, coke, or perhaps awesome quantities of hydrogen? We're not talking about a small colony any more.
Rovers are the better choice if you have enough of a population to justify all those factories. This population could be spread over many worlds if communication and transport are easy enough. "Only two more rover gearboxes in storage. Time to order some new ones." If a few hundred, a few thousand people are on their own, a rover lasts until some vital part wears out. A horse lasts until it dies (and horses die terribly easily). But a fleet of rovers will break down, one after the other, while a herd of horses might breed.
Horses could be brought as frozen embryos and grown in artificial wombs, reducing the storage space needed, so assuming the vegetation here is edible to them, this System could work. It seems a bit unlikely that this alien grass would have all the necessary nutrients as earthly god-fearing grasses, but hey, everything else here is the same as Earth!
Let's break it down into advantages and disadvantages.
Horse advantages:
Horse disadvantages:
Rover advantages:
Rover disadvantages:
Summarizing all this, the key "big value" in horse-technology is that it is a capability that you can maintain with an extremely low tech level and that they can go almost anywhere--on Earth horses can even survive in the (right) wilderness without any human intervention. That said, it is not an easy capability to maintain and requires extremely specialized knowledge to use horses: extensive know-how in training/disciplining, care, medical aid, operation, etc is required. Unlike the skills required to maintain a rover (or a car) these don't overlap much and require a long time to learn so you would need dedicated horse specialists who spend their full time dealing with horses (and grunt labor assistants who shovel shit and whatnot). Modern people generally regard horses in a rather abstract sense (an animal that carries people) but the reality is that horses are an absolute pain to deal with. They are ornery, spook easily, and are generally considered at the very edge of animals that are considered "domesticate-able" (see how zebras aren't).
Rovers--or self-propelled motorized vehicles more generally--don't benefit from the advantages of being biological life: no self-repair or reproduction. They require advanced manufacturing capabilities and a technological support system. This support system generally requires less skill and labor for an equivalent transport load, but that's because a lot of the effort involved has been "frontloaded": engineers have collectively spent man-hour-centuries (or more) developing the tools to make the tools and the designs that go into making the rover. This is how you can have a vehicle that can go tens of thousands of miles with basically no maintenance, and what little maintenance is required, can easily be done by someone "unskilled" with a week or less of instruction or a good instruction manual (oil change, wheel swap, etc).
So, unless you value being able to operate at a "zero" tech level, I would recommend technology based vehicles. Especially in a situation where resources are limited, the horse can easily break an ankle and become crippled for life while a modern, properly-designed vehicle can put up with a frankly ridiculous amount of abuse and still function better in almost all scenarios.
TLDR: Rovers
