Inserting the UM2 was initially a bit of a challenge. The earpieces fit only in the "upside down" position with the cables draped over and behind the ears, and while the Comply eartips provide a good seal, they don't slide in as easily as silicone or smooth-foam versions. But once I got the insertion procedure down, the hassle was well worth it--the UM2 Earphones are a solid step up from the Shure SE310 and clearly the best-sounding in this roundup. In a nutshell, these canalphones are dead accurate with nothing over- or under-stated; detail is clear, bass response is solid, and the overall sound is natural and airy. The audio quality is also consistent across volume levels: there's no weakness at low levels, and there's very little strain when pushed to higher volumes. Compared to even-more-expensive canalphones on the market, what do you give up? The list might (but doesn't necessarily) include heavier-grade construction, a bit more sparkle and definition in the highs, and even stronger, cleaner bass. But this is the one pair of canalphones I really regretted sending back to the manufacturer.

(Note: The first UM2 sample sent by Westone did not work properly due to either a defect or damage in transit. The second unit we received functioned as expected.)

It's worth noting that, surprisingly, none of the phones here sounded "bad." The differences were real and significant, and certainly many fall short of what an audiophile would consider acceptable. Nevertheless, for many listeners, and with the source material found on many iPods, there are many good choices among the canalphones tested. The differences in sound signatures were significant, and personal taste--whether one prioritizes accuracy, bass, or high frequency definition--will play a big part in your decision. And for some, comfort may weigh more heavily than sound quality; in fact, with canalphones, fit and comfort make the choice even more personal, so we recommend purchasing canalphones from a retailer with a good return policy. (Others, and we know who we are, will skip lunch and dine on instant ramen for a month in order to pay for the best sound available.)

The best overall value in the bunch is Etymotic's hf5 High-Fidelity Earphones, which give you great sound quality and comfort for a (relatively) low price. If you're willing to give up some comfort for strong bass response, the extra cash for the Future Sonics Atrio would be money well spent. If you're OK with a more laid-back, unobtrusive sound, the Shure SE115 will save you a few bucks. Each of these three sounds good, but each makes different compromises.