I own both and FWIW each has it's strengths and weaknesses.
There's a million threads about this discussion already and includes posts from myself, Thump, Kannibul and a few other guys.
That being said, my TSL was a BITCH to dial in whereas the DSL sounded real organic right off the bat. I think this is the reason why the TSL gets slammed a bunch...many guys in the in-store tests or bedroom wank fests simply didn't spend much time with the TSL and have the opinion that it sounds like shit. (which it actually does sound like a fuzzy piece of shit unless you tweak it)
My TSL footswitch did take a dump also but reliability on both has been outstanding (several hundred gigs with no breakdowns). I have road cases from
http://www.rockhardcases.com and I baby my gear.
I must say I do like the TSL's clean and the compression on the lead, but you really have to get on it to make it sing. (I do run an attenuator) It's also real fickle about the tubes that are in it. (The stock tubes SUCK) My DSL has sounded great with every brand tube I've put in it. I also really like the TSL if you have a ton of effects in the loop. I've got a separate rack with some stuff in it and it sounds killer. I really don't like v30's or G12T-75's on the TSL whereas the V30's sound AWESOME on the DSL. I run Weber Silver Bells on my TSL.
anyhow, I could talk about it all night but I gotta get to sleep. Hope I've helped.
sub
p.s. play both for yourself and let your ears decide
Overall, I won't choose a "favorite" amp. They both have strengths and weaknesses that give me reason to keep both.