Our first TT was a 2010 Catalina 20RD. After doing a lot of cabinetry and other mods, I was shocked by what I thought was poor quality workmanship. After reading RV forums a lot for a number of years and after owning another brand, I now know that the overall quality of the Coachmen TT was probably above average.
Three negative things I found are that the construction of cabinets, trim, dinette seating, bed frame, etc. was rather wonky and not very plumb, level, square or straight but this is common in the TT industry. The 2nd was that I didn't think the insulation in the ceiling was all that good because there were numerous voids and the insulation was compressed all over causing the overall R value to drop, but again, this is common in the industry too.
The worst thing that was wrong was the brakes. It took the dealer just over a year to fix them and they had what appears to have been grease in them along with warped drums and a broken spring. They kept telling us it was the brake controller. This problem can happen on any brand though.
The cabinets are put together using pocket screws in the frames of cabinets which is a plus. Many manufacturers just staple everything together. The underbelly is not enclosed/heated and the floor is COLD in cold weather.
The dealer was THE worst thing about the Catalina. Very poor service. Besides not dealing with the brakes PDQ as they should have, they were extremely slow in fixing things and it would sit on their lot for weeks. It took 3 trips into them to just to fix a faulty bathroom door.
I wouldn't hesitate to buy one but I would definitely look into the quality of the dealer. I highly recommend going to an RV show and spending lots of time looking carefully at the different makes and models. Look thoroughly inside them (including inside cabinets at construction) and underneath them. Sit down in them and picture yourself cooking, eating, watching TV, etc. Sometimes things can be overlooked and you don't discover things until you start camping in it. Poor locations for TVs are common for ex. Inadequate or poorly laid out storage is another.
Forget about getting a customized order. The plants have routines for doing things and do not like changes. We had some custom changes on our KZ TT, but had to pay a "babysitting" fee of a couple thousand $$ in order to get the foreman and workers to stop in the build process and do something that disrupts their routine. It was highly unusual for them and I don't think they'd do it again.
If you are handy, do modifications yourself. You'll probably end up with something better doing it yourself anyway.