The human eye is a diffraction-limited optical system, and while it has a typical resolution of 60 arcseconds, should have a theoretical resolution of as low as 20 arcseconds based on its aperture - the human eye's aperture being the diameter of the pupil.
It is possible to create a sensor array that can sample an image at the limit of this resolution. Improving the resolution of the sensor beyond the limits of diffraction will not provide any increased clarity - it will merely take additional samples of a blur.
As an example, imagine that we have a point source of light. The optics focusses this light on a sensor. The limits of diffraction means that for a given set of optics, the focussed image of the point source has a minimum size that may be larger than the size of the light source. By adding pixels to a sensor, we merely make the edges of this blurred point smoother.
It is unnecessary to have a sensor array with a resolution significantly higher than the limits of diffraction of the focussing elements.
So, given the theoretical limits of the optics that we can fit into a natural-looking human eyeball, the best visual acuity that we can expect in the visible light spectrum from such an instrument is 20/6.67 or 6/2.
If we are prepared to accept an unnatural appearance, and instead of a pupil diameter of around 4mm, we had a pupil diameter of 20mm, this would improve the resolving power to around 9 arcseconds, giving a visual acuity of 20/3 or 6/0.9. With an orbital size of around 24mm, it cannot be expected that a maximum aperture much greater than 20mm could be achieved.
The possibility exists that an artificial eyeball might deliberately limit its aperture in order to present a socially-acceptable appearance, while having the capability to open its aperture beyond that normally expected for a human eye in order to increase resolution.
As to the question of night vision, it should be possible to construct the lens of this artificial eye in such a way as to allow transmission of infrared light, and from there, the optical sensor could be designed to be able to capture infrared data.
However, the limits of diffraction are dependent on the wavelength of the light in question, and the resolution of near-infrared light might be 120 arcseconds, giving 20/40 or 6/12 vision in the near infrared spectrum. Opening the aperture to 10mm might give a resolution of 80 arcseconds, or 20/26.67 or 6/8 vision. Opening the 20mm might give a resolution of 60 arcseconds, which would give 20/20 or 6/6 vision in the near infrared.
There are other considerations to night vision too. In low-light conditions, an electronic sensor is capable of time-weighted averaging of incoming photons. Since the flicker fusion frequency of the human eye is 15 to 60 Hz, and the sensor would be receiving photons continuously, by increasing the sampling rate and then using averaging techniques, a visible-light image with the requisite frequency can be generated with a higher brightness, though at the cost of increased optical noise.
An artificial eye might also allow optical zooming, though since diffraction limits the resolution of a system of this size, zooming would at best allow a 3x zoom relative to normal human optical resolution, and since this eye is operating at that level already - and we are effectively hand-waving away the limits of the brain to process the extra data - this would be unnecessary.
Given that the limits of diffraction in this system are relatively large, the sensor chip may incorporate a number of sensors in an area represented by a 20-arcsecond field of view. This would include the usual Red, Green and Blue photo-detectors, but might also include an infrared-sensitive photodetector, possibly an ultraviolet-sensitive photodetector, as well as polarisation detectors.
Why polarisation detectors? These would at a minimum allow the selective filtering of optical glare and reflections of sunlight, providing better vision in bright conditions. Then there would also be the ability to see stresses in various materials... the list goes on, and I suspect that only a person with such eyes would be able to come up with a complete list of the advantages.