Why are you only looking at the 22 gallon?
I have a 42 gallon and a 27 gallon Barker totes with pneumatic wheels. I bought them on craigslist for $100 and $20. I have 35 gallon tanks in my trailer. They both came with the plastic wheels, but I called Barker to order replacement pneumatic wheels and they sent me the pneumatic upgrade for free both times. Excellent customer service.
I have not used the 27 gallon tote yet. The 42 gallon tote works great, but if you have to pull it up anything, it can be heavy. I just use my truck pull it to the dump station - handle connected to the hitch ball (Side story: I was at Silverstrand State Beach in San Diego, they have a cement curb around their dump station. I had a hard time pulling it up over the curb full of gray water).
To see how full it is - they are somewhat see through. I just look at the side of it when filling. I have never, and probably will never, used them for black water. I carry it in the shell of my truck and don't want to chance a smell, as well as we can go a couple of weeks without filling the black tank in the trailer.
I would suggest keeping an eye out on craigslist for a used one. It sounds dirty, but both of the ones I have bought have been as clean as new. If they weren't who cares, they are going to get dirty anyway. Just so long as the outside isn't dirty, I wouldn't buy one like that. They can easily be cleaned, and I make sure to do so, no matter how clean it looks when I bought both of mine.