Armor:
Heavy armor like pictured is a bad idea. As pointed out by others, it's going to weigh you down and make you too slow. You might not be bitten, but you'll be caught, knocked down, and probably smothered.
On the other hand, I don't think sports equipment is a good idea either. The protection paradigm is different - sports are primarily concerned about impacts. For example, football or hockey pads are good for your shoulders, chest, and the outside of your elbows because that's where designers expect you to hit. But they don't do much for say, the inside of your elbow/forearm or your lower stomach, because those are low-risk areas. A zombie will easily be able to find ways around it and get a bite into you.
Instead, I would go with motorcycle gear - Heavy leather boots, pants, jacket, gloves, and a full helmet. Human teeth aren't going to go through leather easily, it's relatively light weight, and you can still use nearly any weapon effectively while wearing it.
If you want total protection you may want to find some kind of Gorget to supplement the above, as I think there would be a gap between the helmet and your jacket. Maybe you could get a fencing gorget to work? Like below:

Although I don't know if it would protect the back of your neck, so you might have at least one vulnerable point left.
Advantages:
Armor lets you survive zombies getting in close, or sneaking up on you. Entering a room blind where you might be ambushed goes from "probably get bit" to "very unlikely to be bit".
You can also use it tactically. Presumably you wouldn't do this all the time, but if you know you can't dodge a zombie, this gives you more options. Allow it to bite your protected arm. While it tries to chew through the leather, shoot it in the head (or bash it in the head, depending on your available options). You might choose a different weapon selection if you expect this to happen fairly often, as some weapons might not work well against an opponent who's actively biting you.
The big advantage, though, is that armor gives you that second chance. Without armor, you screw up once and you're dead. With armor, you can survive a lot more screw ups, and since most humans aren't perfect...
Disadvantages:
Even light armor has weight and will, to some extent, restrict your movements. You won't be able to run quite as fast, or as far. If you're not used to it, it could trip you up. In hot climates, you could suffer from heat stroke - imagine wearing heavy leather in a desert summer (on the other hand, it might be an advantage in a cool/cold climate).
Armor also has to be maintained. A zombie bite (or bashing against a door, or falling down) will cause slight damage, and that damage will add up over time. You need to plan on giving your armor regular maintenance and eventually needing to replace it.