We're satisfied with our 32 gal Barker tote. Basically, the choices are Thetford or Barker; two or 4 wheel models; optional side discharge valve. I've got the basic Barker two wheel model. They all have a handle that will drop over your hitch ball so you can slowly tow it to the dump station.
Personally, I wouldn't want to go larger than 32 gal as it's very heavy when full. I've got the top discharge model that requires you to lift the tote vertical to dump it.
If you do go larger than 32 gal I would recommend the 4 wheel model with side discharge, but they're pricey.
We only use ours for grey water as showers fill up the grey tank fast. In 9 years of camping, we've never filled up our black tank.