i got one initially pretty excited, wasn't very impressed, but am now coming around to it.
first off, it sounds great from the audio out. i mean, what you put in is what you get out, but it does it extremely well.
the built-in speaker is ok but basically the weakest speaker you could put in there.
the 1-bar limitation kills me. song mode is kind of a joke when you only have 16 patterns to choose from. this is a pretty big limitation and has forced me to consider this thing in a much smaller role... drum machine - thats basically it.
you can hack it of course to do cool things with step jumps and mutes, but its not worth the effort for me.
what really changed the game for me was the computer editor voysr. another huge complaint i had was that any editing you do on the machine is basically stuck there - you cant dump to computer or export/backup in any way (of course you can record the audio). however, if you build all your programs and sequences on voysr, it saves all those files together, and then you can load up whichever 'bank' as you'd like. it takes a long time though to do this via audio out with a modem tone.
but seriously - i cant stress enough how awesome voysr is. i was building patterns in literally 30 seconds. extremely fast. and such a nice surprise that it runs basically standalone - even with out the volca sample, its a pretty functional little sample sequencer. audio can kind of glitch out at times but its great for sketching.https://www.frederikson-labs.com/
so basically i prep things on the computer, dump them into the volca, and then use it pretty strictly as a backing-beat player when i am playing acoustic guitar. i have done a few fuller compositions with it, but the fact that you cant really save the tweaks has basically prevented me from ever doing anything worth saving on it. i think it would work best at either playing very basic beats (what i do), or devoting the entire machine to one production, so you could have all 16 patterns available. i'm used to squeezing every ounce of power out of a machine, and you hit the limit on this thing pretty quick.
i wish it was half the price - the teenage engineering ko sampler is cheaper and i've heard some dope stuff with that. seems like a totally different approach, so maybe they both have their place.
so yea to sum up, i like it and dislike it for its simplicity, but it does sound good.