Unlike with goats, rabbits are not as complicated to feed. 90% of the rabbit pellets are all the same, just made by different companies.
I have only found, in all my years of rabbit raising, one feed that was exceptional and it had brewers yeast in it (found it at Rural King), and it was the same price as the regular feed.
Rabbit pellets are mostly ground alfalfa and fillers, and are considered a complete feed. But it is best if you give the rabbit(s) a handfull of hay daily, and occasionally give them a handfull of freshly pulled (not cut) grass. You do not want to give them grass cut by a mower because mowers give off fumes and exhaust that stick on the cut grass and can make a rabbit very ill. You must also give the constant fresh water.
Rabbits are social animals to a point, but they are happier if they are in thir own den or hutch. In other words, do not place groups of rabbits in the same pen/den/hutch.