Pros: It comes with 4 different size ear buds so you can definitely find one that fits. With that, these are the snuggest ear buds I've ever tried and they stayed in without a problem through a 5 mile run and 20 mile bike ride. This requires the right earbud and getting them pushed in snugly. Never gotten ear buds to do this. The cord is almost the perfect length for my armband; usually it's too short or long; they are right on the money. They are water resistant (at least after one cleaning); which again is the opposite of every other ear bud.

Cons: All the good stuff (which I haven't found in a pair previously) is erased by underwhelming sound. If not moving, these sound good until I turned it past 16 (out of 20); then the sound started to distort. I listen to electronic music when I work out so the bass just overwhelms these; as compared to my 8 year old Sony sport headbands. I listened to some mostly acoustical music as a comparison and that sounded fine but above 18 (out of 20); they distorted again. Even the cheap headphones allow me to crank. The sound aside, which I'd call serviceable, when you are working out things get worse. I turned the music down for my run/ride and thought it might be a blessing in disguise in saving my hearing by making me keep my music low: however any serious movement caused these to get off-center in my ears and they basically cut out. The sound is still there but it's as if I had them inserted wrong in my ears on each impact of a step; they would then flex back into place and sound fine. Basically on each impact of my foot, these would muffle for a second. They weren't slipping out of my ear, in fact they stayed perfectly in place but it's like the driver has to be PERFECTLY aligned with your ear canal to provide clear sound. I have never seen this before in an earbud. In a way, it almost suffers from having the snuggest fit I've ever seen. BTW, the snug fit block a lot of ambient sound which again was really great. Conclusion: Pioneer managed to do all the things right that everyone else does wrong while at the same time screwing up the simplest thing that even the cheap ones get right.

Overall Review: I got them on a free after rebate, so they'll go into the drawer as an option of last resort. They are okay sound wise but I wouldn't spend any actual money on them.