First things first: these headphones are neon green. Neon colors seem to be somewhat of a deal-breaker for certain people. You either love them or hate them, and all you haters need read no further (we don't blame you). Now that we have that out of the way, these headphones are a design delight from an ergonomic standpoint. Sennheiser's Twist-to-Fit holding system insures a snug fit, even when you're jogging, though this takes a little fiddling at first. Each earpiece has a rubber stopper above it which pushes against the outer ear and ensures stabilization, though the left and right pieces will not necessarily sit in the ear in identical ways, requiring a little adjustment on the user's part to find the position that both is secure and sounds best. The MX 75 also comes with an attractive rubber, semitransparent carrying case, a shirt clip that's attached to the cord, and rubber ear-piece covers to facilitate a snug fit.
Unfortunately, if you can't get past the neon green highlighting, you'll miss out on the entire Sennheiser Sport Line, which includes six earbud styles, all accented in the same color. There's the LX 70 ($54.95) with an ultralight headband design; the MXL 70V ($44.95) with an incorporated lanyard; the OMX 70 ($44.95) with adjustable ear hooks for a secure fit; the PMX 70 ($49.95) with an ergonomic neckband; and finally, the MX 70 ($34.95), which features a design similar to that of the MX 75 but also incorporates magnetic earpiece faces for connecting the earbuds around the neck when not in use.
Once properly in place (again, this can take some work at first), the MX 75 earphones really shine. On The Fiery Furnaces' latest album, Bitter Tea, every experimental sonic nuance--from the creaking and squeaking of old organ parts in the right ear to the lead singer's often rapid-fire, bizarrely metered delivery--was a completely intelligible delight. On the upcoming debut album from CSS, Cansei de Ser Sexy, guitars fuzz as Brazilian temptresses coo over deep bass beats, and the MX 75, while not exactly an eardrum rattler in the low-end department, provides something much better: low-end clarity. Kick drums thump with ferocity rather than boom with shapelessness and distortion, and the crispness of the high-mid frequencies rivals the quality of some Sennheiser studio models.
It's hard to say whether the Sennheisers are a better buy than their close competitors in the Shure in-ear line, but for our money, they're definitely worth an audition: they stay in place better than the Shures and sound just about as good--but it ain't easy being green.