I have some experience (a few gigs) with the TSL. The clean channel seemed pretty un-dynamic, so I used the crunch channel for cleans, just turned down the vol know on my guitar a bit. And the 3rd channel is just like cranking up a Marshall preamp with an overdrive pedal.
My overall impression of the TSL was that it wasn't that responsive to the sound of my guitar, it somehow lacked personality, in lack of a better term. It's an ok amp, but I'd never buy one new.
Remember, a good quality responsive tube amp and a good overdrive pedal plus the range you get by fiddling with the controls of your guitar can produce a vast variety of sounds. The versatility is more a matter of your guitar and your playing skills, IMHO. If you already got a good amp, find a guitar that sounds useful with every combination of controls, and off you go! My current main gitbox works fine from metal to country to blues to funk and back. It took me a while to find all those sounds, but it sure was worth it.