My man Mike @ Vertex Audio hooked me up w/ 2 sets of these for my brother's car. My first impression was that they are some beefy little buggers for the price, and remind me of my CF components. Very well built, especially for the money. I spent the day installing them, deadening his doors, and building some nice mounts for them. All in all, I am VERY pleased to have used them. They are the best coaxials I've worked with to date.
We powered them with one of the new mid-line Pioneer head units, with a 5 band eq and pretty decent quality overall. They sound great from 40hz, and the tweeters extend well into the upper range, and w/ a little blending from the eq, I got it to sound excellent.
Build quality: 9/10
Overall, I'd give them damn near a perfect score, as far as coaxials go (on a relatively small budget, I mean). They are, pound for pound, some of the nicest coaxials available.