Rather than a one-size-fits-all approach, RHA have included a choice of 7 different-sized buds. This means that when you receive your headphones, you're going to have to fiddle around for a bit and agonize over whether you have oddly shaped or abnormally sized ears. But once you've found the right buds for you, you can start to appreciate the benefits of the MA450i's sound quality and noise exclusion.
I tried these headphones out with everything from lilting singer-songwriters to the abrasive tones of chiptune -- and they performed brilliantly. If you're into music as an emersive, atmospheric experience, you'll really appreciate these earphones. Sounds are sharp, the bass performance is impressive and different layers of music actually sound like different layers rather than an indistinct mulch. They are definitely the best earphones I have found in this price range.
What I really appreciate about these headphones is the "made-to-last" feel about them. For example, the cable is sheathed in fabric - the stated reason is to avoid tangling, but more than this it gives the earphones the feel of a quality product -- a wide step apart from the scratty tubes of plastic on my old iPod earphones, that got twisted and crimped and pulled apart long before their time.
The earphones feel like they can take a lot of abuse from being thrust into bags and pockets. But I don't want to test this yet. For now, these are my babies and I'll be coddling them for a while yet.