I use TPU in two of my bikes. Tubolitos in one and Pirelli P-zero in the other.
I had to patch a tubolito at the seam in the tube but their patch kit worked. The seam leaked, it wasn't a puncture. They lose air like a butyl tube and need a pump once a week. They're made in Asia somewhere, I dont remember...
The P-Zeros have had no issues and after two months haven't lost any air that I can tell.
The cost is the issue. I just bought retail to start off with and thought Id look for a cheaper source if I liked them. The Pirellis are $40ea retail but If I can cut that down, I'll put them in all my lite bikes. I think they had made in Austria on them.
I haven't tried any other brands yet but I may if this thread reveals any good reviews. Right now I'm good with the Pirellis. 35 grams per tube is a big weight savings over a butyl tube.