I traded a recent Tube Screamer for this and I've never looked back or regretted it.
Vox Valvetronix SE. I don't think they make them anymore since all the other modeling pedalboards (like the GNX) come with lots of other things like recording software, drum machines, loops, etc. This just has effects and amp models. You can save them into banks so its a breeze to switch between them. I have some banks programmed with amp models for when I'm running through the mixing board and other banks without the amp & speaker models for when I'm running through an amp.
As far as how it sounds... I know its blasphemy for a guitarist to say this, but I prefer it to using an amp these days. I can hear myself in the monitors better than ever, I don't need to crank anything too loud to get the sound I need. And I have a versatility that I did'nt get when I was using two overflowing pedalboards. The overdrive and distortion sounds are far better than average, the chorus/phase/flanger sounds are all great (but I rarely use them since that's not really my thing), the delays are fantastic, so are the reverbs. The wah does its job too.