I'm a professional percussionist, currently on the King and I tour, and I had to buy a new set of ear plugs to replace the Elacins that I left at home (whoops!) I was going to go for the Elacins again, as the string they're on means I can whip the plugs in and out as necessary, but decided to try the Alpines instead based on the excellent reviews they had.
When they arrived I was very impressed with the 'bonus' ear-plug you get - it's nice that they recognise how easy it is to brush one off a stand and lose it forever, especially if you're a dopey musician! The filters themselves are a bit fiddly to put in, and there's definitely a knack to it: remember not to squeeze the plug too much as you're putting them in otherwise they won't go all the way.
Once the plugs are in your ear though, wow! Amazing clarity of sound yet at a reduced level. I was worried I'd have to take them out when playing quiet unison sections with the woodwind, but I can still hear everything perfectly clearly with them in. And then when things get loud (cacophonous tam-tam or cymbal rolls especially) they take enough edge off the top-end to preserve your precious hearing. Also other percussionists will be pleased to know that with the pronounced middle-high frequency roll off, you can hear fundamental notes a lot more clearly, which is great for tuning timps (or hearing how badly out of tune your glock is!)
The little carry case they come in is a nice touch, don't know if I'll be attaching it to my keyring anytime soon, but I'm sure some may find it useful!
So to sum up, I would heartily recommend these to everyone thinking of buying ear plugs. The sound quality is much better, in my opinion, than the Elacins, and the three different filters mean you can find just the right amount of noise reduction for the situation.
As a side-note: If any club-goers are worried about their hearing yet don't want to wear dorky sticky-out-of-ear-plugs, then these do the job perfectly because they sit far enough inside your ear to be completely hidden from the front, and they really help you hear what people are saying(/shouting) to you in a noisy club!