I've never had a Basix transmission or known anyone that did, but there has been a bunch of times I have seen GTP's for sale that had bad transmissions, and I wanted to buy that GTP then swap in the Basix and flip it.
I had the good fortune to pick a solild built transmission for my 2001 and haven't needed to worry about it so far, but if I ever need to a transmission, I would be more than likely to grab up a Basix.