The TS is a good kite, it's powerful and versatile for both TT and Surf. A friend of mine used to ride for Best and compete in the surf with the TS, seemed to work quite well for him. I also rode it many times in various sizes, was happy with the performance.
The kites did have some issues with valves so you'd want to check those carefully, there also were recalls about faulty CL quick release (hard to release) and also another issue with the safety line not sliding properly through the bar. I've had some scary moments with those faulty safety systems, so I cannot recommend the bar safety wise.
Also you may be interested to know that Best doesn't exist anymore.
kiteforum.com/viewtopic.php?f=1&t=2396495A lot of pages to read about this, but the short version is that the owner/investor is behind bars and there is now a new brand which was recently launched by a few previous Best employees. This new brand is called Eleveight Kites. As you can see their kites look a lot like the Best...
I wouldn't expect any support or warranty (even if you were willing to pay for it) in case you have any issue with a Best kite.
Christian