Now that I've had a couple months with these, I thought I'd come back and post my impression of them.
As expected, the H3's don't rise to the level of performance of my high-end IEM's (Ety ER-4P, Heir 4.ai, Grado GR8), but even so, they're still quite good. They compare most closely with the Grado GR8, so that's what I'll use as the reference point.
Sound quality is not in the stratosphere, but is still very good, bordering on excellent. I would characterize them as very relaxed and neutral sounding - they are very easy and pleasant to listen to. As it turns out, I find this characteristic is just perfect for taking phone calls and listening to audiobooks, where intelligibility is critical, but any sibilance or 'bright' characteristic would be fatiguing and undermine the usability for extended listening. The H3's are softer and drier sounding than the GR8, somewhat less lively and less transparent (consistent with their tendency towards a non-sibilant, relaxed sound - this might be considered an asset given the intended usage). The H3's are also a bit congested by comparison, lacking some of the delicacy and refinement of the GR8's, but I am pleased to find that these B&Os are no slouch! I am very happy using them for casual music listening on the go or at the gym (where the inline controls are very welcome), and it's only when I want to sit down for some serious music listening that I turn to the better phones. To round out the comparison, I find the GR8's are smaller and lighter - thus more comfortable, while isolation seems similar.
Speaking of isolation - the H3's are OK. Nothing extreme, but enough to get by. I think it's about what one can expect from a single-flange silicone eartip, being oriented more towards comfort and quick / easy insertion than towards maximum isolation, and I'm fine with that compromise. In an office environment, for example, I find the GR8's far more usable than the 4.ai's, simply because I can pop them in and out so much faster - if a colleague stops by for a chat, there's no awkward maneuvering to extract a deeply-seated earpiece before the conversation can begin. The Beo H3's fit in the same category - quick and easy to don and doff, and therefore more convenient in most day to day situations. I did recently have occasion to test these headphones on an airplane - I realized after settling comfortably in my window seat, that I had forgotten to pocket my usual earplugs (still in my bag, now stowed well out of reach in the overhead bin). Then I remembered I had the H3's in my pocket, so I decided to put them on in lieu of a proper earplug - something's better than nothing. They got the job done, cutting ear-splitting announcements down to a reasonable amplitude, and keeping the engine roar under control - I had no dreaded tinnitus ringing after the 3-hour flight. I even used them during the flight to listen to part of an audiobook, and they worked out just fine - I did not have to jack the volume up at all. So I would say for airline use, the H3's isolation is minimally acceptable - it'll get you by on a short-haul, but I really prefer more isolation, especially on a long-haul flight.
As far as sound leakage goes, I have to say I don't find it to be an issue at all. Covering up the eartips with my fingers, there is little if any sound escaping out the back of the drivers. So I'm not sure why others commented that they have a lot of noise leakage - it doesn't seem to be an issue with mine.
Fit & finish on the headphones is excellent. The metal body of the transducer is quite hefty and robust, although it isn't uncomfortable in the ear, nor does it feel like it's going to fall out. The carry case is very good - again, excellent fit and finish, holds the phones well, and offers good protection. However, the case is a tad bulky (it's a little tall, and I wish it were lower profile for better pocketability). Indeed, I end up carrying the headphones coiled up in a jacket pocket most of the time instead of using the case, but the case still stays in my work bag and gets used when I don't need to have the headphones immediately at hand.
Ergonomics are also very good. I find the H3's very comfortable for extended periods - they sit securely, and despite their apparent heft, they don't feel like they're at risk of falling out, nor do they cause any discomfort. I have a couple of minor quibbles - the H3 is not petite enough to stay comfortably in the ear while you lay your head on a pillow (to be fair, very few IEMs can pass the side-sleeper comfort test), and second, the mic and controls are on the left-hand side. Since I do use these headphones for taking phone calls, I will sometimes leave only one ear in, with the other hanging loose, especially if I'm in the car where it's essential not to block your awareness of the sounds around you. My preferred choice would put the controls and mic on the right-hand side, but I wouldn't call this a deal-breaker for taking phone calls. The dangling ear piece is a bit pendulous due to it's weight, and I find it needs to be held on to or tucked behind a jacket or into a shirt pocket to keep it from swinging around.
The inline controls are OK - nicely styled with decent buttons and click feel, though I find it a bid difficult to consistently distinguish the middle button from the 'up' and 'down' buttons by tactile feel alone... I usually have to run my fingers up and down a bit to find the ridges and orient myself before clicking. The extra time and attention required to operate the inline controls is just enough to stand out as a lump in an otherwise smooth experience. So some improvement could be used here - the crummy Apple earbuds which came with my iPhone have a recessed center button, and you can tell in an instant whether your finger is positioned on the middle, top, or bottom button. Though it's a bit of a subtle issue, I find this to be a constant annoyance - probably my one real peeve with these phones.
Overall, I find these to be an excellent day-to-day headphone for varied use (not just intense audiophile music listening). The H3's absolutely destroy mass-market earbuds, are great for casual music listening, and are near perfect for audiobooks and long conference calls. For the price paid (about $135 with a special discount), I think they're an outstanding value. Even at the regular list price of $200, I think they're still a good value, but you can sometimes find the H3's new at about $150 if you shop around or wait for sales.
Quick summary:
- Very good but not excellent sound quality - great for extended listening
- Comfortable with good but not great isolation
- Excellent fit & finish, great aesthetics
- Good ergonomics, with exception of tactile orientation of controls, left-side mic / buttons, and thickness for side sleeping
- Very good value for a high quality all-purpose headphone