Like others, we have owned both (and before the TT a Pop-up camper
After towing and living in our 5er the past 15 months, I would never consider going back to a TT. Stability, resistance to Semi's vortex, resistance to crosswind sway all make a 5er so much easier to tow than a TT.
I like the living space better than a TT as well - Rockwood has done some cleaver engineering to the ceilings to make the living areas seem huge. (not that they are small by any means
Depending on the size of 5er, you can safely pull it with a 1/4 ton P/U (OC, B&B, & I do) The 2015 Ford F150 Ecoboost with the HD Trailer package can tow a whopping 11,700 lbs!
Sure if you are going to get a big 5er rig you will rapidly move up the line to a 1T Dually Diesel.
You really did not touch on what you will be using your new RV for? Are you going to be 3/4-full timing it? Do you have any future upgrade plans? Do you have a good idea how large a unit you will be wanting (Anything larger than the rigs OC B&B and I pull will put you into at least a 3/4 ton truck.
Finally, the larger 5ers like Cedar Creek, Cardinal, and Wildcats have all the amenities found in top of the line Class A rigs - this is not something you will find in the TT class.