Three hundred and fifty bucks is a lot of cheese for a pair of earphones. But these Klipsch Image X10i thingies, they rock. Be forewarned: There's no point in shelling out $349 on headphones if you're not listening to high quality source material. So if terms like "lossless format" and "high bitrate compression" are foreign to you, pass up the X10i in favor of a quality, lower-priced headset like Klipsch's own $99 Image S4i. Not only will standard quality mp3 files not justify the X10i's price tag, but in Kipsch's own words, these premium earphones may actually make your low-quality music sound worse:
If you rip your digital music files using a poor compression format and low bit rate, this high-resolution Klipsch headset will uncover all the flaws in your content.
Kudos to Klipsch for being up front about it. If you're not into high quality digital music, there's no reason for you to consider spending $350 on a headset. But if you are, man you're in for a treat. The X10i performed like a champ for me, and I actually found it to yield a better combination of comfort and noise isolation than my previous favorite in-ear headset, the Etymotic hf2.
Klipsch's design is dead-simple and wonderfully light and comfortable in its minimalism. Unlike other canalphones that actually require inserting a plastic eartip into the outer ear canal for maximum performance, the X10i worked great for me using the single-flanged silicon plug eartip. The tips don't actually penetrate the ear canal at all, but rather sit in the ear like standard earbuds - the difference being that Klipsch's squishy silicon eartips fill the outer ear, effectively sealing your music in and unwanted sounds out. While most canalphones - X10i included - come with both single- and double-flanged eartips, the latter designed to fit inside the inner ear canal, these are the first set I've tried that worked best for me using the single-flanges. Again, that's all just to say that I got great sound and noise isolation without jamming anything into my ear. And while I'm used to jamming canalphones into my ears (it's perfectly safe if you're using quality 'phones), I found that the X10i design was easier and more comfortable to use for longer periods of time without sacrificing any audio quality. I also found them much more to my liking than the slightly different design of the those Image S4i I mentioned earlier. In other words: The X10i's fit is awesome.
Speaking of awesome, so long as you've got properly high-quality source material, the X10i sound terrific. These are about as good as in-ear earphones are going to get until you jump out of consumer-grade territory and start dealing with custom ear molds and four-figure price tags. You won't get thumping bass from the X10i, but that's not the point. The point is accurate reproduction of audio across the entire spectrum, and these 'phones make that point with authority. A trained audiophile could probably make the case that the X10i lack a bit of midrange clarity, but I could be wrong there. I basically just enjoyed myself while listening to rock, electronica, jazz, funk, and everything in between with these puppies discreetly tucked into my ears. So long as I made sure to skip the low-quality files, that is.
The X10i also feature an inline mic and remote control that's "Made for iPhone" certified. Three buttons on the remote control play/pause and previous/next track, and can be used to accept and hang-up on calls. Full mic/remote functionality is limited to iPhone 3GS users, though I got spotty/random/totally unreliable response here and there with a few BlackBerry and Android phones. X10i's cable is 48" long and affixed with a straight 1/8" jack at the end. The cable is noticeably thin and a bit more susceptible to tangles than other headphone cables, but it's not really anything to worry about.
X10i's microphone was slightly disappointing, but fine overall. I'm not a huge fan of the microphone's placement, as it hangs down at the base of my neck during use. I find I have better luck with mics placed along the cable of one earphone or the other, as they hang higher and off to the side during use. Also, for as high quality as the earphones are, the microphone seemed to be a step down. It was fine, but lacked the wind- and background noise-cancellation performance of a few other headsets I've tried recently. Still, X10i performed pretty well during calls, and an included shirt clip can be used to move the mic' to a more preferred position during use. The headset also comes with a handy carrying case and 1/4" and airplane adapters.
All in all, the Klipsch Image X10i is arguably the best earphone-style headset available for iPhone users. $349 is a lot of money for a pair of earphones, they're only fully functional with iPhone 3GS, and if you're not listening to high-quality audio files there's no point at all in using the X10i. But for the discerning listener who already has a 3GS loaded with lossless music files, these babies are as close to audio nirvana as I've yet experienced. Lightweight, comfortable, and capable of solid audio reproduction and noise isolation - the Klipsch Image X10i are champs.