sure.
i'm not too familiar with the tsl as far as the EQ section etc goes. i only know how it sounds when my other guitar player is playing, who's using EMG loaded guitars into his tsl, crunch channel for rhythm, lead channel for leads....i'll stick to the rhythm for now. EQ wise, he tends to crank his gain (as it's the crunch channel), bass slightly past noon, treble, presence, and mids all around noon, all buttons (deep=bass boost / tone shift=scoop) disengaged
i can tell you that the 5150 has quite a versatile EQ section. as i already said above, you can dial in anything between marshall style midrange grind a la kreator and rectifier-ish rhyhtm's a la the latest arch enemy record (if i didn't know better i'd swear they used the 5150 for that one....it's dual recto/krank btw). the 5150 has INTENSE amount of gain, can get quite noisy if you go overboard with the gain though.
the 5150 has more bass response, WAY more actually. the 5150's crunch channel has slightly lower mids and even more bass than the lead channel which has more sizzle and bite. the marshall sounds like shit at low volumes, whereas the 5150 can get some decent low volume sounds, too, although it really shines at high band volumes like most tube amps.
i'd say that you could get REALLY close to the tsl using the 5150. the 5150 is somewhat fizzier, though, although it can be dialed out and my ears might fool me on that one because the 5150 is quite a lot brighter than the marshall (believe it or not...). i'd say that the 5150 has even higher mids than the marshall, although not as high as my old jcm800.
to put it in a nutshell, the 5150 is more versatile, has more gain, does NOT have a decent clean channel, is brighter than the marshall with a higher midrange voicing, and has no trouble cutting through a wall of marshall sound. in fact, both amps mixed together sound HUGE. my soundguy loved the 5150 since the day i started using one....he says it's the shiznit for anything from 80's thrash to swedish death metal. i agree.
