Summary: They're great for sports, but terrible for listening. I pretty much only use these if I'm going running or something now, and have other headphones for everything else. Overall I was a little disappointed, but when I got them they were on sale for 20 bucks, and had a 20 dollar MIR, so for a free pair of headphones I have to say the hassle was worth it.
Pros: Strong cables, good rubber, and a very comfortable fit make them ideal for running. They also can be comfortably looped over the ears to get them to stay on while running, and I haven't noticed any problems from sweat.
Cons: The sound quality is bearable, but not much better. Music sounds pretty bad, and voice from audiobooks or lectures is scratchy and hard to understand, especially if the recording quality was only marginal to begin with.
Summary: With the above qualifications, music is clear and accurate and non-fatiguing on these earbuds. But unless they're super sturdy (and I haven't owned them long enough to say) the price doesn't seem justified. Maybe wait for a good sale...
Pros: With less expensive earbuds, a particular frequency range is often emphasized, which can actually be fun. With these Pioneers, the emphasis is on "mid highs" – I'm guessing around 4 to 6K – which puts the focus on snares, hi hats, crunchy guitars, high pitched instruments, and the upper regions of vocals. It's an adventure – you might hear things in familiar songs that you've never heard before...
Cons: On the other hand, bass frequencies are virtually absent. Maybe this is a trade-off for the waterproof design. Whatever the reason, it's just not there.
Pros: I use it in the gym and the adapters have a size that fit's my ears pretty well. Ownership period based on having pink version for several months.
Cons: This is the insanely long mailing address for the rebate: Pioneer SE-CL-331-L 3.5mm Connector Canal Water-Rersistant Stereo Earbud Earphone for sports (Blue) Promotion #49113-PR PO Box 22094 Tempe, AZ 85285-2094