I bought this with the intent of making my life easier when it comes to recording guitar. But found out it also made my life easier live-wise: I now run an ampless guitar rig, with my dirt boxes before the unit, and my mod/time-based effects in the loop, running straight into the mixer/PA. It has 2 12AX7 so it still ads some warmth, and also bite, to the sound.
It has 2 Channels: Clean and Dirty. And 2 more subChannels in the Dirt: Crunch and Lead. So you have everything you need, for every kind of situation, in one compact box. The Cleans are super clean, sparkly and transparent, my chorus and reverb pedals love it. The Dirt channel can go from a JTM45 type of saturated overdrive, to close to a JCM800 type of gain. Very tight and very transparent, as well.
Overall, it's a great box to have around the studio and live, even if you use an amplifier live, this can still save your ass if your amp breaks down. And you won't even notice the difference.