portable holding tanks

I agree with the above there is no best. I have the Thetfold one. I got the biggest 35 gallon. My grey and Black are both 30 gallons so I'm good even if full. This one has an automatic stop so you don't overflow and out of all I looked at it seemed the strongest as well as most user friendly. Also but not needed, I have a flojet pump and with a few adapters I've put together I can pump 50 feet away into the tank into the back of my truck. Many times the dump station is way to far or rocky to use the pull with car method.

http://rvcampersuppliesandparts.com/rv-portable-waste-tank