I would look at getting one with a non-Lippert frame. Jayco and Lance use a BAL frame that has no welding on it and is good. Some other manufacturers use it and you could always call BAL and ask who. Nash and Outdoors RV (Northwood) build their own in-house heavy duty off-road frame which is good. Stay away from ultra-lites that have the type of frame that is made from 3-pieces of mild steel welded together and *looks* like a regular I-beam - much weaker than a regular I-beam and can/will eventually have issues. (You can just run a finger along the vertical/horizontal part of the beam and feel the roughness of the weld instead of kneeling down.)
Look closely at tire and axle ratings compared to a TT's GVWR rating. It is always safer to assume a TT will end up weighing close to it's GVWR rating (max. it should weigh) when it's fully loaded for camping along with mods & upgrades you may have done. Some TTs have ample cargo carrying capacity (CCC/NCC) and some have the opposite. When some TTs have one or more full holding tanks, a TT (like ours for ex.) can even exceed the GVWR. The axle rating will be on a sticker on the axles and max. tire loading will be on the tire sidewall. Some manufacturers do not provide much spare load capacity (20% is a number often recommended) and tires and axles can be loaded to near capacity. Load on tires will not be even (more on one axle and/or left or right side of TT heavier) resulting in overloading which can lead to tire failure and bent axle(s). I was looking at a Keystone TT on display recently and it had this situation. Not only that, it had the 3-piece welded frame and spread axles which will further add to potential problems. You need to deduct the tongue weight (estimate using 13% as an average, but can be up to 15% in some cases) from the GVWR to get the actual load sitting on the axles/tires. (Take 13% and multiply that by the GVWR rating and then deduct that from the GVWR.) If available, upgrading to optional higher load range tires can be a good idea.
Personally, I would avoid a TT with spread axles. Because a trailer's axles have different turning radii in a turn, one set of tires gets dragged across the pavement and is hard on tires. Spread axles exacerbate this.
If you want to start with what should be a better quality TT, stay away from ultra-lites. They are built to be as light as possible and are typically built with the lightest and least substantial methods and materials.
If you want a real education, go to one of the factories and see how they build these things like in this
Jayco vid for ex.
It's also not just the quality of a TT that matters. Some (many??) dealers can be atrocious and turn an otherwise great TT into a nightmare. Similar thing can happen with some manufacturers. Before committing, I'd see what you can find out about a dealer and factory.
Man, oh man, there's just so many things to look for it would take pages and pages. Hard to reduce down to a handful of recommended manufacturers. Some can have a particular make & model and totally love it, while others can have lots of problems and hate the same one. Friends of ours have a Keystone Cougar TT and some of the construction quality is dismal (cabinetry, ex.). Met a Keystone TT owner recently and his TT had major roof leakage. Took it to the dealer who only made it worse. Then it got sent back to the factory who took it apart to repair it and while it was better, it still leaked. From this and other things I know, I would not recommend Keystone. Some love their Keystone units though.
