So for the past few years I've always wanted a set of really bad ass speakers. I've gad good speakers and great sounding speakers, but nothing truly "bad ass". I had been looking for Kenwood XXV-04s components for a long time, but never found a set at a price I liked, and ended up buying these instead. They definitely met my expectations.
Sound quality wise, these speakers are fantastic. They're a very flat speaker, you really don't need to set an EQ to make them sound good. I ended up setting a slight EQ on them just to bring them more in line with my personal listening tastes.
Power handling, these are beasts. Rated for 100 each side, I see no reason they couldn't take more. I'm giving them just around 100RMS and they're taking every bit of it with no issues at all. Honestly if you're putting out more power to these than they can handle, you need more set of speakers.
Midbass and bass. This was a big one for me, as my old speakers were lacking in this segment. I'm a bit of a midbass snob, I like my front bass. These speakers are not going to make people think you've got a set of subs if you don't. They don't have the punch that you'd get out of a true subwoofer, but they do have some kick to them. Their actual midbass range is spectacular, I listen to a lot of rock music like Chevelle, and they make the deep guitar lines sound great. Just don't expect to not need subs by buying these speakers.
Midrange on these speakers is a tough one. Very good vocal sound quality, but an issue i wasn't expecting does show itself here. The tweeters on these are larger than normal speakers, they're a 1.5" tweeter IIRC (or something close to that in mm), where most comps come with a 1" or smaller. So what this means is that the tweeters on these play lower than most other tweeters, so much so that they pick up almost all vocal ranges. This makes for a very different than normal experience. The vocals still sound good, but at some times the tweeters can overpower the woofers, making for a strange sound that's sharper than normal. Some people will love this, I ended up adjusting my EQ to soften this some.
Highs are great, the big tweeters are very loud and sound good. Just be prepared for the size of these tweeters, they're huge.
Detail, these speakers produce a fantastically detailed sound. My previous speakers were pretty detailed, these are even more so. You hear everything.
Build Quality is what you would expect for an expensive set of components like these. The crossovers are huge (no really, they're HUGE, be aware of their massive size when planning your install, they probably won't fit in your doors) with attractive plexiglass covers. The woofers have a gorgeous carbon fiber cone with a brushed aluminum phase plug (that can be removed to mount the tweeter like a coaxial speaker), with a very shiny chrome cover over the magnet out back (why you'd have a chromed piece on the back of the speaker is beyond me, but its an attractive speaker regardless). Everything is well protected for shipping, and the box itself uses a very nice high density foam for packaging. The attention to detail in the build is astounding, the grilles (it comes with 2 kinds, a mesh covered one and an open one) have little foam backings inside them to keep them from rattling. The speakers have very nice push style connectors,no annoying spade terminals or screws to connect to the speakers. The tweeters have their leads pre-tinned, so you just need to tin the wire you're using for them and solder them up
Value is a tough one, if you're tight on cash forget these, they're $550 retail. They sound great, but they're not really designed for bargain seeking customers. They come with NO wire outside of ~6" coming off the tweeters. With speakers of this quality/price you'd probably end up using different wire even if they came with wire, but it'd have been nice for them to at least throw in a roll of 16GA speaker wire. At $550 you can get a lot of really high end speakers, and there's a lot of competition at this level. The QS isn't really a "technical" speaker, there's no neodymium magnets that weigh nothing yet have lots of power, there's no crazy tweeter designs, no magical properties, and no concessions to make them thinner. They're just big, beefy, great sounding speakers. I'm completely satisfied with them, but I wanted beefy speakers like these. They easily can hang with all the other speakers around this price range, and sound better than most of them, if not all. But they are $550, and I can't say they sound twice as good as a "high end" $250 set of components. So if you've got the money, and like this type of speaker, you'll be happy. But if you're stretching your budget for them, don't do it, the law of diminishing returns has definitely set in by this point.
Sound Quality: 9/10
Power Handling: 9/10
Build Quality: 10/10
Overall, these are great speakers if you've got tastes like mine (more muted and balanced sound). My buddy had a set of Kappa Perfects in his truck, and they are noticeably "brighter" and "sharper" due to their metal tweeter and cone. The QS gets lower and deeper, but you notice the Perfects more. The QS has a better build quality IMO, the Perfects had their dust caps blown off eventually. The Perfects have smaller crossovers and tweeters though. The only other real thing I'd say is that if you didn't have the means to adjust your EQ well (a factory radio for example), the RS might be a better choice for you as they come with the smaller tweeters that shouldn't cross into the woofers range as much.