So, it has the features and the comfort, can the MM 50's deliver a sonic performance to be proud of? Given these are a more entry-level offering you won't benefit from clarity to match the likes of Etymotic, Shure or even Sennheiser's own more expensive models, but it should go without saying that they're still head and shoulders above the ear offending nastiness of the iPhone bundled set.
On first inspection it's immediately apparent that the MM 50's are deliberately bass heavy. This makes for quite a departure from the flatter and crisper sound of the Etymotic hf2s, to the point where the same track can sound radically different when listening on the MM 50s. Primal Scream's 'Uptown', from the new album Beautiful Future, illustrates this well, with the bass line on the MM 50's becoming rather over powering and all encompassing to the detriment of the vocal line and overall composition.
Of course, for the intended market this probably isn't a bad thing, but the promotion of bass over everything else creates a boomy and muddy sound that comes across slightly un-natural and forced. It also means percussion driven tracks, like 'Reckoner' from Radiohead's recent album In Raindows, sound rather flat and lifeless.
On the flip side, it does add a nice level of punch and drive to Hip-Hop, Dance and R'n'B. Take the driving bass drum from Daft Punk's 'Human After All' - it's so loud and dramatic it feels like you have a bass drum wedged between your ears. If this sounds good to you, you'll probably like the MM 50's a lot.
This doesn't negate the fact that there isn't a great deal of subtlety here, though. High frequency clarity is passable but nothing special and when confronted with complicated compositions, like 'Reckoner', or a classical piece like 'Jupiter' from Gustav Holst's The Planets, the MM 50's sound a little dull and uninteresting.
Our only other concern with the MM 50 iPs is that the build quality isn't that astounding. Protection around the wire entries on each earphone isn't exactly heavy duty and neither is the wire itself. Given the lack of a protective case, you'll want to be careful how you treat them.
If you're after a relatively inexpensive but generally good iPhone headset to replace the bundled offering, the MM 50 iPs make a good case for themselves; they're well designed, comfortable and the headset functionality is well delivered. Moreover, if you like your music bass heavy, you'll enjoy the sound they deliver, too. We do feel, however, that the bass bias is a tad excessive while the build quality isn't up to the standards normally expected in this price range. Neither of these issues are deal breakers, but they're factors definitely worth considering.