For me, I had an 18.5ft TT and now have a 21ft Class C and I found (again FOR ME):
1. I prefer backing up in the C over backing up with the TT for several reasons. I travel alone, so I don't have a spotter; nighttime visibility was much lower with the TT (my C has large windows on both sides and the back); the combined length of the TT and TV vs the C made maneuverability more difficult.
2. The C is better suited for day trips and quick departures. With the TT, I had to hitch up, and parking it in a regular parking spot was less than desirable. The C, I just hop in and go, and park it just like my SUV. I drove the C to work one day and we used its kitchen for food prep and storage, etc.
3. The TT was better when at campgrounds because if I wanted to head out on a side trip for the day, I could just take the SUV. With the C, I am taking it all with me. This can be a problem if someone goes camping with me, but would prefer to stay back at camp when I do a side trip.
4. With the C, I don't have to think ahead as much as to what I need at hand for the drive. I can easily pull over and grab a soda or snack or camera, etc. while on the road. With the TT, if I didn't think ahead, I had to find a place large enough to pull over in, then walk around the vehicle on the side of the road to the TT in order to get what I needed.
As to distance driving, I find the C is more tiring than my SUV. But, otherwise I prefer it. On highways, I had idiots try to merge into my lane BETWEEN my SUV and TT (that doesn't work), so I was having to maneuver around them. On backroads and in town, I find the C easier to maneuver.