Perfect for gigs love the tone.

Sounds great, versatile unit with compression and a wide range of tone options.
Two flaws in my opinion
Tuner is unreadable in sunlight
Won't work off phantom power, and a 9v battery lasts maybe 10 hours, 3 or 4 shows for me. Can take 9V adapter but that's an extra step I don't like to take.

When I used it with a Taylor acoustic (2021 model with Expression System II) there was a hiss when the signal passed through the EQ. When I bypassed the EQ (via the "pre | post" switch on the back) the hiss went away. I did not have this issue with the other instruments/mics I tried. I returned it as I was primarily interested in it for the Taylor and the guitar just sounded better without it, and the guitar doesn't have these issues with other equipment I have used (several pedals and a Yamaha THR30iia amp).

It does not come with an external power supply (currently $15 here) or a 9 volt battery.

Overall I recommend this if you need something like it...it's got a lot of cool features and is overall it is a good price point. If you have no pedals or an amp then this can really help you tune your sound. The one star off is because I think it should handle all guitars using standard interfaces as well as a lack of it including an external power supply.

Preamp sound is really good with my MartinD-41. Built-in tuner not exact match to pitch of my other tuners. 'No reason this should not come with the A/C power converter. 'Had to purchase that after the fact. G-r-r-r-r. Overall, reliable, balanced with lots of pre-amp boost.

UPDATE: The schertler BASIK set was a complete disappointment, feel free to check out my scathing review of that to see screenshots of the feeble output. I tried to make it work, and this preamp made it at least possible to use with drastic boost and EQ, but it was not easy. After 2 gigs I returned the Schertler, but this preamp is excellent (plenty of boost, nice sounding EQ, nothing else I know of has class a circuitry, 2 gain stages and useful mid sweep, all powered by a 9v battery, honestly I think it is the coolest thing Fishman makes). I'll be keeping it for the custom JJB electronics piezo I'm having made (for less than $30 by the way.)

ORIGINAL REVIEW:
Using it on a gig tomorrow so if I run into a problem I'll update. I bought this for my new koa Island ukulele that I don't want to cut into. I bought the "low end" schertler BASIK pickup (still $160 freaking dollars, not overly impressed for the price) which sounds quite good, but sends a VERY low level. Why go cheap(ish) on a very expensive Uke? Because it's the only stick-on pickup designed for 1/4 passive inputs, and I play through an assortment of preamps, amps and processors, most of which don't send 48v or have XLR ins for instruments. Someday if the situation calls I'll sink $500-$600 into a Schertler or DPA high end unit, but for now I want the never-fail 1/4" solution. And even with this preamp, it still costs less than the high end stuff.

The low level of the BASIK led me to a preamp. I'm a fan of the brassy Fishman sound, I need it to be battery powered, and I'm also a bass player, so this seemed like a good fit.

This preamp has a lot of parameters and takes some time to dial in. This is ultimately a good thing. Since I need a lot of amplitude, it was tricky to find a balance between the trim and volume that didn't introduce too much hiss. But I got a good tone after a while, and also determined the middle of the low cutoff choices was the best for my low g Uke. The eq is excellent and very easy to use. With this setup, and the Fishman cranked, I now get to the level of my Godin acoustic/electric nylon string guitar at half volume (the Godin onboard preamp is incredibly powerful and virtually noiseless so about half volume is what I usually use). It's a pleasant, vibrant sound, and the sweepable mid and treble controls dial down quack and brasssiness nicely. They're both cut quite a bit, and bass is left flat, I'm glad I didn't go with a simpler preamp since my tone needed a lot of shaping for my unique situation.

I'm confident my tone will be good tomorrow, but I'm also sure I'll be tweaking plenty of knobs. I'm ultimately happy and impressed with this preamp for the time being.