Just got one of these. Haven't read anything in this thread yet other than this last page which included @jumblemind and @sloppy_phil 's reviews. 2 of the most spot on amp reviews I think I've read on Talkbass

. I find myself a bit more in agreement with jm though. I'll do my best to add whatever I can...
I'll start with the disclaimer that my first test was running it at a rehearsal through a crappy cab (GK 8X10 with 4 of the speakers blown and removed

). Yeah, it's a horror show, but I've played through it lots, and I'm used to what it can and can't do.
Getting distracted by a few things so my apologies if the writing here doesn't flow well

....
Anyhow, I must say that if this were my only head it would be a no go. I'd absolutely send it back. I bought this only as a backup, and because I want to stack to heads to use the Rick in Rick-o-Sound mode on my new bass with my 2 15s. My other head is a Carvin BX700 and IMO one would have to be on a massive amount of drugs to choose this TC over that. The 2 don't even compare. And the Carvin only costs about $40 more. Makes me wonder a bit.
What I like and why I'm going to keep the TC: I like that I can fit it in my gigbag, and I like the toneprint because I want to mix my Ric with a clean and distorted sound. I don't like using pedals, and want LESS to carry, not more. I also need a backup as I had a head crap out on me once at a gig, and I never want to repeat that experiences. I have some PTS from that incident, and I've been carrying a spare head everywhere I go. I'm going to keep it because I feel it CAN hold up in a small to medium gig if I needed it to, and at low volumes I think it does the job. Tone is OK, but only up to a point.
What I don't like about it: It's severely lacking in something I can't quite put my finger on. Lows? Thump? Punch? It gets loud enough and is EQed to cut through and be heard, but it really sounds like half the amp the BX700 is. And I don't think it's just a wattage/volume thing. It's like it's missing a whole bunch of frequencies, and important ones, too. I asked the guys I was playing with to turn up a bit to see how far I could push this, and again - it cut, but in a really pathetic sort of way. And I had the amp cranked, bigtime, like on 9. Fiddling with the EQ at that point became almost pointless because the amp was working so hard to just keep up. Oh hwell... maybe I was just expecting a bit more out of that 250 watts. Maybe it'll wow me when I plug my 2x15s into it.
Last disappointment for me was the way the EQs are set. I know they boost and cut different frequencies to supposedly give a wider array of sounds... but I was unimpressed. The only usable sounds for me are between 10 and 1 o'clock on the bass and mids, and I had the treble pretty much cranked for cut. In lower volume situations that might have been different.
One thing I'll give TC credit for is quick customer service. Their user manual and online help left a little to be desired, but I emailed them 2X - once about the UTIL button (which is a hole, not a button, and I didn't feel safe sticking a paper clip in there as I suspected I needed to), and the other was with tones not loading (didn't know that only the bass amp models would load)... both times they got back to me immediately.
I'll chime in again after I use it with my 15s, but that's all I got for now.
Oh yeah... What's the mp3 stuff you guys are talking about?