I bought this to have more control over my tone, I play an acoustic guitar with a Fishman pro blend installed, they work together quite well.
The EQ filters are what I was looking for, you have a low cut knob, bass, mids, and treble and another called 'brillance' which works like an upper treble filter. You can select the frequency affected by the mid knob, something quite useful to cut those muddy mid-range tones that feedback so easily when amplifying acoustic guitars.
Compressor, tuner, input trim, boost... these features are useful to some extent.
The tuner has an accuracy of +5- cents, it could be better as some clip-on tuners can get at +3-.
When I wanted to keep the input and boost levels fixed, had to stick some tape over them, otherwise it's easy to mess up the levels, a thing to be aware of when plugging in an amp or hitting the boost!
By the way the boost is a nice feature, say you're playing rhythm full on with the band and here comes your solo, boost some Db up and cut through!... I find the minimum setting boosting +3db is quite enough for me!
Compressor is also good for when you play a mix of stumming and picking as it will level up the dynamics making your stumming sound a bit quieter and you picking louder but I would not abuse of it.
It works with passive and active pickups, with passive you just have to adjust the input trim and you'll get a good signal.
The battery lid seems a bit flimsy and the battery itself feels like is wanting to spring out of its placement, there is not a fixing connector, so I'm afraid if the lid breaks I'll be forced to buy the power supply.
I was waiting for it to come out last year, the best for me is having all of this analogue filtering features plus a tuner in a small stompbox and I'd say it was worth the wait and the money.