I can not comment on the others mentioned here in this post, but I can comment on RodentPro.com

I have used RodentPro.com for rats, rabbits and GPs. I only ordered rabbits from them twice. Both times they were junk. They smelled bad, poop and dirt all over the bags and rabbits.

The rats and GPs I have never had a problem with and they have always been pretty nice.

Its to my understanding that RodentPro.com breeds very minimal feeders, most are bred by others and then bought by RodentPro.com and re-sold by RodentPro.com. I'm not sure if this is true or not.

This could be the reasoning for their inconsistency in quality.