I’ve been using this on and off for practicing and testing ideas for almost a year now. For my purposes, it is perfect. I play a jazz bass (funk, jazz, soul, r&b), and I have no trouble getting the nuances I want. The sound is rich and clear, and the volume/gain/lowpass give enough control to adjust the sound to something that works comfortably on headphones. The output definitely goes high enough (on Koss Portapro). Battery life is good, I’ve been using the same batteries for 10 months (but I don’t play every day). The controls work fine, though they feel a bit flimsy, due to their small size and plastic material. The onboard effects are ok, I could take or leave them. The overdrive circuit works fine, but I don’t use it.
Overall it’s one of those really useful products that makes you pick up your instrument a bit more often.