My experience of owning TC amps was far from dreadful and last year I sat in a room with Nathan East, while he played with the best tone I've heard in a long time from an RH750 and a TC RS212 cab.
So far, since 2007, I've played through an Ampeg SVT3 PRO, Markbass LM2 and F1, TC Staccato and RH750, Thunderfunk 550 and 750, Genz STL 9.2 and Aguilar TH500. I could get a great sound out of all of them, except the F1, and the band liked the F1. I have good basses and good cabs and maybe my technique is more forgiving but IME if you can't get a good sound out of an amp then you're doing something wrong.
I've played and heard amps and cabs I didn't like but I'd always say that was down to my preferences and not a problem with the gear.