FYI, Bestop makes the factory ones as well.

 

I have the frameless bestop. I forget the model but it is the chespest one and while it does the job and is easy to use, it is extremely loud.

 

I guess one of the decisions you'll have to make is if you want to go completely topless or bikini top. I never had the Trektop NX but my understanding is it doesn't fold down you just remove the Windows (I'm sure Trektop NX owners will correct me if I'm wrong). Another drawback I see to the Trektop is loss of cargo area do to the slanted back. I have the Bestop Supertop NX (has frame) and can fold it completely down or put it back up in minutes. It's a good top no leaks.