I've always hated using the Apple supplied earphones. I have three sets on my desk here, all unused, and I'm fairly sure I have a set at work and a couple of sets that have died over the years. They're awful, they fall out, are too quiet, have terrible base and a tendency to fail (left ear first). The microphone and controls on them were always fairly good, but that's really not enough to make them usable. They were particularly abysmal in a loud environment. Good luck hearing anything on a bus without deafening yourself in the process. I also tend to listen with the volume low - literally one or two notches from silent is enough for me to hear music perfectly in most circumstances - except with Apple earphones; they need 50% volume or greater.
So, I always ditched them, and most often in favour of noise isolating canal-buds. I have most recently been using RHA MA 350s (which have developed an unpleasant buzz in the vocal range recently, making listening to podcasts in particular a bit annoying. The 350s have otherwise been pretty awesome). I picked canal-buds primarily because as with the Apple earbuds, almost all other earbuds are too small and tend to fall out.
Canal-buds come with their own problem though: prolonged use irritates my ears, and regular prolonged use makes it worse. So long as I took them out for a while every so often, this was a manageable problem. When Apple announced the EarBuds however, I was instantly hopeful that they might offer a good compromise, a design and shape that offers good sound quality and usability, but also didn't irritate my ears.
What I can tell you about the sound is not surprising: the EarBuds will not rival high quality, noise-isolating canal-buds. They are the best earbuds I've ever used though. The bass is good, strong and not as fuzzy as it was with the Apple earbuds. It's also richer, and I can hear details that were previously drowned out. The mid and high ranges are simply excellent, and voices are very clear. I had some Sony earbuds a while ago that cost significantly more but were nowhere near as good. On sound quality, these may be king of the earbud format, at least until you're prepared to spend the better part of a hundred bucks.
They don't isolate at all, really, so you're still going to have to crank the volume a little in a busy environment - that's no surprise though.
They are also very comfortable - they hook in and rest and through general use have yet to fall out. due to the way they hook into the ear, their small size doesn't affect their ability to stay in place. I'm not sure how secure they'd be if you were running or being otherwise vigorous and active while listening but I think for most people these are going to fit really well. They are very well shaped, the sound is aimed the right way (earbuds generally requiring to sit at a slight angle in my ears) and it seems that Apple's approach to the shape and fit has paid off.
They are, for the moment, probably the best compromise for me.