HF2/3/5 all have the same drivers and sound - the difference lies in their remote/mic options.
I think the HF5 is a perfect choice for you. I have listened to the Grado 225i and Shure SE215 for a few weeks each, and used to have the HF5 for years before I upgraded to the ER4S. The 225i and SE215 are definitely in the same 'class' of sound signature as the HF5: detailed and fairly neutral. However, the 225i had a little too much treble energy for me, and the bass rolled off even earlier than the HF5. The SE215 has considerably lower-reaching and louder bass than either the HF5 or 225i, and great sound stage like the 225i (the HF5 lacks a bit in sound stage), but I found it to be too much in the SE215 and it muddied the signature for me.
The HF5 is just clean, clear, and crisp. You will hear things you never heard before. It's like waking up in the morning and stepping outside under the sun, where your eyes can barely keep up with all the light. Your ears will have a hard time at first keeping up with all the fresh detail in the HF5, but you'll soon grow addicted to it. The biggest drawbacks to the HF series, conversely, is a tight/small sound stage, and the bass doesn't go as low as competitors, and the treble doesn't go as high as competitors.
It's almost like the 225i and SE215 mated, minues the wide sound stage; but the detail and energy more than make up for those drawbacks. Not to mention the isolation is world-class and makes it easier to get lost in the music and shut out the world, without blasting your music.
For ~$100, there's no better option out there for clean, flat, smooth, detailed music in an in-ear. If you want to get your feet wet without spending that much, the Soundmagic PL50 at around $50 sounds very similar but not quite as energetic, and the EtyKids (around $40) I've read about it sounding similar but is very hard to drive (purposely) and I don't have experience with it myself.
