Figured I'd pop in and give my $0.02.
I've owned my CT for about 5 years now. It's the most expensive thing I've ever bought in my life. My honest opinion on CT basses is this:
As others have said, Carl's build quality is second to none. Flawless craftsmanship and fretwork. While they're unlike any other basses in the world, they're actually supremely comfortable, ergonomic and lightweight. I love the neck on mine; it's incredibly fast, yet has enough girth to give the proper hand support for my large mits.
... That said, the tone does leave something to be desired, for me. When I first got the bass and plugged it in, the first thing I noticed was the piano like tone/sustain of the E string, which is quite impressive. But overall, the tone is very dark and "wooden" sounding, without much focus on "tightness". I agree with the people who said it seems like he builds them to appeal to upright players. Sadly this is not what I desire for my basses. I've thought about either trying installing a preamp to add the "punch" and tonal clarity I desire, or just selling it off and buying a bass more suited to my sonic needs. On the one hand, it is a uniquely beautiful collector's item, plays amazingly and I've got immense respect for Carl and his work... On the other hand, for how much I could sell it for, I could buy several amazing instruments that sound better for my purposes, and have some money leftover.
I'm still mulling it over... but if it's possible to get the sound I want out of it with the right preamp, I'd 100% want to keep it. If anybody has any input on going this route, I'd love to hear it.
-BB