Very good I think as long Eneloop batteries verrchten their service (5 hours continuous medium volume). Annoying is that the amp sometime at a certain discharge level just goes out at peak levels. So always have a set of fresh batteries this is advisable. And you can already, via the THR Editor in USB mode on computers (Win / Mac) to tinker his favorite sound. The last setting remains Offline USB received in Amp.
incidentally, the THR is also very good as a speaker for music and as a "sound card" (for Recorden etc) - The sound is really very lively and wide. One should not expect miracles bass, but they are playing quite crisp.
. A great amp is better to use two of them;)