This unit is very fun to play with. When I bought it I thought about something that could be taken with me on tour, used during gigs, and also afterwards on the tour bus. I am not a keyboard player, I just wanted to add additional sounds to the band. During the tour, the inbuilt speakers entertained two bands in a van during two weeks! :D The quality of the sound through the inbuilt speakers is acceptable. After 70% power you can hear a huge decline in quality, but hey, they are meant to be plugged into a line anyway. The sounds are very good, when you finally get to plug it into a mixer. You can get various sounds, from 70's synth pop to contemporary drum'n'bass heavy synths and nice pads. The built quality is good, but not great. Especially for the keys, they are made of cheap plastic and one of mine broke during the tour (I didn't have a case for it, my bad- it's still usable anyway). The rest is pretty neat though. It's very colourful, and the fact that you can run it only on batteries is outstanding! The only thing that really lacks in this synth for me is no "latch" button. Really a shame, because I feel like it would have been an even better option for musicians (like me) which normally play a different instrument. You could just latch one key and play along with it. Overall I am really satisfied with this product, can't wait to get more synths and connect them with midi, to start a synth-centipede. :D KORGOZORD!