Summary: The big issue that I have with these headphones are that they aren't that comfortable for people who have larger ears, like me. The headset clamps comfortably against my head it's just after 1/2 hour my ears will become uncomfortable. If you have ears that are more flat against your head, I don't think this will be a big issue. To be fair, I have this problem with most headphones though, except earbuds. Most of the pressure is on the top of the ears and just above them. If you wear glasses, I could see this could getting very painful really quick.
The headphones are very good quality though. I know they have a good range as I can even hear the extrememly high pitched hum that my sound card makes(very annoying like a hearing test w/only one really high frequency, but is a problem w/the sound card).
I am very pleased w/the open-ear design of the headphones. Although my ears still get sweaty with them on, it's not nearly as bad as wearing regular closed-ear cans.
The microphone itself is a rigid plastic that swivels about 200 degrees. The mic cannot be moved physically closer to my mouth which can make it hard to hear your voice in playback. It has very good sensitivity and picks up my voice pretty decently even though the mic is about 4 inches to the side of my mouth. Although, enabling the 20db boost in the Volume Control allows my voice to come through loud and clear without yelling. It doesn't pick up much background noise as I talk, which is a plus.
For the price, I would definitely recommend this for anyone looking for a decent quality headset and would even purchase it again. I would even recommend this to people who have larger ears, if they don't mind taking them off for a couple of minutes every hour to let their ears relax. I would seriously NOT recommend this headset to anyone who would wear glasses while using this product.

Summary: It was a decent set until my left side cut out right after the 30-day warranty expired, which I find annoying after throwing 30 bucks to replace my last headset which had the same thing happen to the right side. Arrrgh!

Otherwise this wasn't so bad. Music playback wasn't all that great, but I didn't buy it for that reason. I bought it so I could take advantage of Battlefield 2's VoIP comm system. In that regard, It worked fairly well although my buddies did claim that my voice sounded a bit low and they often heard some slight background noise. Unfortunately, you can only swing the microphone up or down, and not closer or further away. Likewise, you can't adjust the headband, although for me this didn't cause a problem (until the sound in the left ear cut out, that is).

Then again, Logitech has been known quite often to prefer style over function. This was one of those times when they seemed to have missed the sweet spot.

Summary: I bought these as a replacement for an old set about the time Battlefield 2 came out. They were amazing all summer until about a month ago when one side of the headphones no longer worked. I dealt with it for a week or two then stopped using them for the last two weeks until i tried them out again today, and now there is no sound at all! In my research for a new set I found many reviews (mostly on newegg) that said the same thing about the sound going on one side.

They may be uncomfortable to start, but that isn't such a big deal. Unless you find a really good price on these, don't buy them because they seem to have a major design flaw with the sound. Otherwise, excellent, while they last..