It's time to settle this debate. I've been posting a lot (in the "I need a $100 IEM category") about Shure's entry level being the best value out there. However, I STRONGLY feel that the PREVIOUS generation Shures are better than the CURRENT generation Shures.
The reason isn't because the drivers are different or anything (the drivers are the same). It's simply BECAUSE THE PREVIOUS GENERATION SHURES FIT MUCH BETTER AND GO INTO THE EAR CANAL. The newer, say SE535, doesn't go into the ear canal nearly as much as its predecessor, the SE530/SE500PTH. Same thing with the SE215, 315, 425, etc.
Because the current SE215/315/425/535's design doesn't allow for the tips to go deeper into the ear canal, you're losing bass and isolation.
The Shure SE115/310/420/500/530 and even SCL3/4/5 go much further into the ear canal, sealing off outside noise much more effectively than, say, the SE215.
All this being said, of course, there is the detachable cable upgrade in the newer generation. This doesn't really matter because Shure's generous 2 year warranty covers everything should something happen. They have the best customer support in the business (mail in your IEM's w/ receipt and get a new pair a week later).
All this being said, IMO, to answer all your "which is the best IEM around $100," I've answered SE115 or SE115m multiple times. Great bass (but not overwhelming), but most importantly, THEY GO INTO YOUR EAR COMFORTABLY. The newer SE215 (same/similar driver, despite the newer "215" name) doesn't go in nearly as well - it sticks out too much and doesn't seal as well losing sound quality.
So ironically, I strongly feel that the previous generation is better.
I've owned every single Shure IEM model, and here are my top picks. Don't bother with the SE210, 310, 315, they are just too neutral and boring.
Higher end: ($200-400)
E500/SE530PTH (same model)
What are y'all's opinions?