I was looking for a set of headphones for commuting purposes, but am not a fan of IEMs (in-ear-monitors), so closed back cans is the best I could hope for. Full-size headphones do tend to look a little ridiculous in public, but these relatively small, supra-aural (on-ear), closed-back Sennheisers looked to fit the bill. I will start, then, with isolation (where they were, sadly, not enough for my needs).
In short, they do not isolate well enough for general commuting. On the train (at least, on a more modern, better insulated train), however, they are perfect. They isolate well enough to listen at reasonable levels and not lose detail to background noise. I suspect, though cannot be certain, that they would also be suitable for using on a coach. With music on you will likely not be able to hear enough to have a conversation, but you will be able to hear if someone requires your attention (you can hear voices, but not enough to make out words). Unfortunately, the majority of my commuting takes place on the bus, and here they do not block out enough of the engine and tyre noise. On the rare occasion I catch a double-decker, they were good enough to use on the top deck, but if it is very busy/there is a lot of chatter they are again not really enough. I like to be quite sealed-off from my surroundings, though, so they may be enough for some. If you're on the fence on this, I think it's worth a shot. On the bus you'll lose some low-end detail (unless you have them dangerously loud), but the music is still 'listenable'. I have not had the opportunity to try them on the plane as yet, but I don't think they would block out enough noise there for you to have the volume particularly low and still hear your music clearly. They'd certainly be better than any of the in-flight 'phones, though, in every respect including isolation. On the plus side, they leak very little noise to the surroundings. As I said earlier, I think they were excellent when on the train, and I know that the person sitting next to me won't be annoyed by my music.
The sound quality has already been covered here and elsewhere, and I agree with most other reviewers. For their current £50 price they are very good. At original RRP I would certainly not have been unhappy, but probably less impressed. Compared to the usual warm Sennheiser house-sound, these are more neutral. I find the highs to be rolled off slightly (emphasis on slightly there), giving a smooth sound which is great for longer listening periods. Despite the roll-off, I don't feel that it has taken away too much detail at the top end. I am a bit of a Grado fan, and they are known for being bright headphones, but I still enjoy these. The mid range seemed to me to be pitched just how I like it - not put forward or recessed relative to the highs and lows, but in balance with them. There's a reasonable amount of detail there, too, though these are by no means an analytical sounding headphone; I find them to be rather enjoyable to listen to in a non-critical manner. The bass is punchy, tight, and not at all boomy, but still definitely hitting those low notes. This matches well to my preferences, and so I had no need for bass-boost functions, however, they will take an increase in bass without distorting if you want it. Bassheads should look elsewhere, though. The soundstage is remarkably good for a closed-back headphone, and they sound far more open than I was expecting. Obviously, it's not up to the standards of open-backed, full-size headphones, but it is more than enough for me not to feel at all cramped-up. I mostly listen to rock, classical and jazz and they hold up well in each. Their smoothness lends itself to the sort of jazz I listen to. I can't comment on the burn-in period, as whenever I get new headphones I always let them do 24-hours or more of playback before I put them on. It saves me from the occasional disappointment of a headphone the sounds poor out of the box. This review should be taken as burned-in.
Build quality is good, with some minor concerns. The strain relief at the jack end is stiff enough not to provide all that much relief, in my opinion. At the headphone end, the relief is very short, again leading to the same problem. The cable is thin enough to bend freely, but feels pretty strong. Only prolonged use can really tell with that one. The headphones themselves are very light, but the steel(?) through the headband makes them feel a bit tougher. I am not convinced that the plastic will stand up to being chucked into a bag every day, but if you take care of them they should last. The collapsing mechanism is excellent, as is the arm-length extender, though I am worried that these clock-into-place parts might wear down and no longer function over time. When folded up, these would almost fit into a shirt pocket! There is a supplied travel bag, though I don't see it offering any protection other than keeping them clean since it is a soft case.
Comfort wise there is not much to say other than that they are comfortable. I've worn them for periods of a few hours and only suffered mild discomfort, what with the plush ear and head padding. I think I would prefer it if the head padding went all the way across, rather than just being at the sides.
These are easy to drive from something like an iPod, though I find I need the volume a bit higher than I do with e.g. my Grado SR80s to get the same volume. The in-line volume control is a bit of an oddity; it doesn't feel like it will break at all, but I don't ever use it, just leave it at full.
Reading this you might be wondering why they haven't got 5 stars, since isolation is my only real problem and they are not marketed as a block-all headphone by any means. I like to reserve 5/5 for things that really are flawless (or as flawless as they can be). Taking into account RRP and my build-quality concerns I can't put a 5 down just yet. If they're still going strong in 2 years' time, I'll come back and change it to 5 (if I remember, and they are still in production).