I have been using the SE215 for about a week now which were replacements for lost Etymotic hf5 (big bummer!).
Here are my thoughts:
SE215- full, warm, rich sound, somewhat weak highs, strong but not overpowering bass, good noise isolation, burning in even richer sound. fit ok-but i may order the yellow foam which did not come with them for a tighter fit. still trying to get use to the over ear cable design which takes longer to put in and secure around the ear than the Etys; the cable is both longer and thicker than almost all others in this category-- over 5 feet long--too long for my uses-gym, bike, travel--but not a deal breaker.
HF5- a different sound experience than the SE215: clarity is totally amazing and superior, no boosted bass like the Shure making for very clear bass w/o the overboom I dislike and others really like. Fit-you can get complete noise isolation with these and feel like you are in your own world-be careful when biking--which means you get the most utilization out of the incredible clarity and at lower volumes which is easier on your ear (hearing loss is an increasing health problem).
I love both earphones for different reasons: the fit, ease of in/out, superior sound isolation and clarity of the HF5 is hard to beat. These are easier to put in/out, so better for grab and go gym, bike riding. If you are more patient than me, it'll take you 30 seconds more to put in the SE215s. The superior sound isolation of the HF5s can be a hazard if you are biking or moving around--you really are lost in another world with these on which is ultimately why I love them. As for types of music, classical is definitely better on the Hf5s which are superior in terms of clarity and highs, and if you prefer thumping loud bass over more clear rhythmic bass, the SE215s win on that count. All that said, I'm not sure which ones I prefer for electronica and hip hop-- the clarity of instrumentation and range of the Hf5s versus the pumped boom of the bass on the SE215--hard to choose for me.
Both companies provide excellent customer support. The SE215 fit flush against the ear, while the HF5s stick out a little. In fact, I broke a pair of Ety MC3s a couple years ago due to this design (i think) while biking with them. However, Etymotic offered to take most of the price of a replacement pair off what I then purchased, the HF5.
Both are great earphones. Just think about how you will use them and about your sound and fit preferences. Even better, try them out if you can. Some folks recommend ordering your top 2 choices, knowing you'll keep one and return the other.
buena suerte!
