I've ordered from most of the big US companies just to compare. In terms of feeder quality, my absolute go-to is Layne Labs. If I lived on the east coast I'd order from Cold-blooded Cafe or Perfect Prey. I won't order again from RodentPro just based on the notably lower quality of feeders in the orders I placed with them.
Humane treatment of feeder animals is really important to me, and I will say that in telephone discussions, Layne was head and shoulders above any other company in that arena - but if you don't live in the western side of the country, their shipping may not compare well to Cold-blooded Cafe or Perfect Prey.