Very well built and everything feels quality. The sound is exceptional! The clarity and depth is just astounding. I can hear stuff in songs I've never heard before. The bass is of course a little lacking, but for 4" it is still very good. I'll be buying a subwoofer to accompany these to get access to the full range of frequencies, so not an issue for me.
For those concerned about the hiss that some people complain about, all monitors with Class D amplifiers produce a hiss, but these have a switch in the back where you can reduce the output level to lower the noise floor. The hiss wasn't bad even before flipping the switch but after I did, it reduced it to a very low level and made it almost inaudible.
All in all I'm very happy with my purchase! And they look cool too! :)