As this is a wired in ear set, you definitelly won't have sound quality troubles, all you need to do is get a great pair in In Ear Monitors to plug into this and you have an awesome concert experience.
The only downside to wired in ear is that you are connected, it kinda limits how much you can move across the stage, but if you're a drummer or a keyboard player this is awesome for you,and on a really low budget a perfect solution. Even if you're a guitar of bass player you can tape the xlr cable along your guitar cable and have the two of them together and that makes it quite simple, as you're already used to be on one cable, just one other isn't too much of a problem especially if they're taped together ;). Only where I wouldn't recommend this is if you're a singer, you'd be tripping over wires the whole show ;)
As for the build quality, it looks pretty sturdy, though the clip on the back looks like it might be the weakest part of the system, though I may be proven wrong, I guess we'll just have to wait it out and see if it will stand through the tough road use ;)
The system sounds great, of course you must know how to make a great mix for yourself, and you shouldn't pump too much volume coming into the device as that will result in the limiter kicking in too early, rather make a more silent mix and turn in up on the device itself, as it has a volume knob on it ;)
All in all, for the price a perfect solution ;)
Definitelly beats the floor monitors :D
And like always, great and fast service by Thomann