1st impressions: very good. Sounds like any TS's but has no annoyances and doesn't change the sound much at all.

I have only played it in front of my Tech-21 so far, but it does exactly what I wanted it to do. I never play totally clean, and this thing is REALLY good at taking your existing sound and kicking the hell outta it. Adds very little noise or anything, retains the clarity and string separation, but makes the sound sing and scream. That's exactly what I wanted.

From now on, when I record guitar on my TM-10, I'll surely kick this in rather than tweak a beefier solo sound on the amp, it's so good.

The only thing it does I don't like as is, it makes the lead sound a bit too warm and thick...sustains forever and has that kind of 'roundness' to it...at all knobs on 12 o clock and in front of my already crunchy TM, I get this instant Gary Moore Still Got The Blues - sound. Sustain forever and very very thick and warm but screaming. Thing is, I like it more raw and biting...but a little addition of treble on the pedal and all sorted out; again closer to Angus Young territory.

Will post more when I get to properly test it with the Ceriatone, but so far, this is probably the best lead booster/crunch maximiser/OD pedal I've ever used.

With no drive on the amp the sound is very 'blues' and round, but as said, I never play totally clean. Basically it sounds like any other Tubescreamer out there, but there's no noise, no annoying overtones or anything...it just BOOSTS whatever drive you have to umpteenth potency in drive power.

Thanks to whoever it was who recommended this baby when I asked for something which would do just this - it's much better than I expected, even!