TT buying is a three legged stool.
1. Floor Plan - Most important because it is a constant reminder of you choice.
2. Tow vehicle - You need cargo capacity that will handle the tongue weight and camping gear. This is often the weak link in the chain.
3. Cost - It is a hobby that you might grow tired of or not get to pursue as often as you wish. It is supposed to be a hobby not a financial burden.
All three of these have to be balanced to match your budget and life style.
You can tell the better quality TTs because they cost significantly more than a similar sized unit. That is thousands of dollars more.
Most of the popular brands are hammered out in northern Indiana using the same labor force and construction techniques. Hence they all seem to have about the same quality track record.
The TT industry makes over 300,000 TT and 5th wheel units a year. A few turn out to be lemons. A good dealer can help considerably.
Good luck and enjoy the RV lifestyle.