Okay, I've got the MotoRokr S9-HD for $51.99 plus shipping and here are my thoughts after having them for 1 month.
On the sweat thing, I'm not noticing any problem yet. I sweat when I walk/jogging and I go out in fog sometimes or light mist. So condensation has gotten on mine.
Sound is pretty good (think $20 sony headphone quality) with the surround sound setting the only one I'll use. Otherwise the sound seems too treble thin. I like the earbud covers. Seals well around the inside of my ear, and I've had trouble with other earbuds and seating in my ear. I don't use these to mow my lawn and the volume is always kept way down. These can go pretty loud. When I walk/jog next to a road I don't even turn them up all the way. My hearing is that of a 49 year old, so I thought the volume performed well.
The build, quality and sleek low-profile design style makes you look cool with these. A plus in my book. After all I have a stylish iPhone. Why not stylish wireless headphones?
The charge seems to hold fairly well too.
Receiving phone calls work perfectly (music quiets and comes back up after the call). The call quality to my caller is a bit less than a dedicated bluetooth headset with noise reduction when I'm walking outside in a windy environment. This is probably due to the fact most dedicated bluetooth headsets direct the microphone closer to your mouth, whereas the Rokr's are farther back. Inside the house or in quieter environments though it compares to a good quality bluetooth headset, if just a tad quieter in overall call volume to my caller.
The only thing I can say bad about these is something that plagues all wireless headphones. Namely, that the wireless bluetooth signal generated by devices, such as the iPhone, compress the signal that is sent to the wireless headphones and that means there is something like a 1-second or less compression/converting lag in the audio when you watch video. So, keep in mind these or any wireless headphones may have a slight lag in the audio of the videos you are watching on the screen. I have to say I was disappointed, but it wasn't a dealbreaker for me.
These are still wonderful for listening to music and podcasts on-the-go. And I appreciate the lack of wires to deal with and the low profile in wearing them around others.
For $51 plus shipping I'm still glad I bought them.