Having used both of these earphones
Having used both of these earphones, I think they are both great. I tried to break it down point by point below in a way that will hopefully help others make the decision without trying both, but if you have a chance to try them both then you absolutely should! Everyone has at least one bandmate with an SE215! Bass: tie - the SE215 has deeper bass but the bass is a little bloated. Having tried a friend's SE535, I can say for shure (Hah!) that this is not a problem with the higher end model, maybe just a limitation of only having one driver. The MX1 lacks presence below 100Hz in comparison, but the bass is also clearer. Just down to preference here. Mids: SE215 - definitely stronger and richer mids on the SE215, to the point where sometimes I feel the frequency balance is off. But for both live monitoring and general music listening, the mids sound better on the SE215. Treble: MX1 - the story here is the opposite of the bass - the SE215 has a more subdued treble that seems to run out of steam earlier. Overall: MX1 - while I like the mids of the SE215, I feel the overall balance across the frequency spectrum is better on the MX1. I assume Shure pursued this sort of sound on purpose, making the SE215 more bass-heavy to appeal to "normal consumers" who may be more prone to buy the entry-level model, and also saving more balanced sound profiles for the more expensive and musician-focused SE models (which are, by the way, fantastic and absolutely worth splurging for). Comfort: tie - both have a similar design, the SE215 is fits better with the included foam fittings for me while the MX1 wins once customised. Having looked into getting 3rd party custom eartips made for my SE215, and then actually gone ahead with having them made for the MX1, I can say the latter is much more affordable and straightforward Noise isolation: tie - the Shure foam tips are superior because they go deeper in the ear, and last longer as well. However, you can get custom sleeves made for the MX1 which are even better. So if you don't intend to get custom sleeves, the SE215 is better, but otherwise it's a tie. Value: MX1 - while the sound, comfort, etc may all be called a tie depending on your ears and preference, the value is hard to argue with. Not only are they cheaper to buy, they come with a spare cable AND additional replacement cables are much cheaper. Definitely a money saver in the long term.
