I used to feed both Pro and Gro and I always had good results. I did find that the does on kits did just fine with the Pro, so I stopped paying the extra for the Gro. If a doe is looking rough while feeding bunnies, I just add some BOSS (black oil sunflower seeds) to give her more fat. Our rabbits don't seem to actually need the extra protein.
The only reason I stopped feeding Manna Pro is that when shipping became astronomical it went to $38/bag, and it wasn't reliably on the shelves. Changing feed brands around can really throw a wrench into rabbits' guts. So now I use a pellet made locally. I'd be happy to use Manna Pro again, though, if things changed.
Manna Pro also makes an affordable rabbit pellet called Small World that you can find in stores like WalMart. It seems to be good quality as well; I used it when I couldn't find Manna Pro. But it only comes in 10 lb and 25lb bags, so not really convenient for me (we go through 50lb bags fast enough).
Manna Pro is a feed company that makes all sorts of animal feeds. Their rabbit pellets come in Pro, Gro and Sho, with varying amounts of fat and protein. They also make a product called Calf Manna that many rabbit breeders use as a supplement. (I have used it that way, but have found BOSS to be just as effective and a lot cheaper.)
