Pros: Cheap, good battery life, good sound quality, easy to operate with one hand
Cons: A little loose on the ear
I've had this now for only a few days and use it walking around and sitting at my desk. I get bad reception so place my phone (BB Curve 8310) at the window and sit ~8 feet away at my desk. It has been very clear so far and although it feels a little loose on the ear, I've spazzed my head around in an attempt to dislodge it to no avail. I also have very small ears - from top to bottom it is smaller than the headset unit length-wise less the earhook.
The reason I like it so much is the price. At 16.99 from buy.com with free shipping and handling for 3-5 business days delivery it's a bargain!
Have not yet had any problems with hearing people and no one has complained about the sound coming from my side.
To test the battery life, I re-connected with contacts over a three day (probably 8 hours or so talking) period without recharging it and it has just low battery with the repeated high tones.
It's very easy to put the headset on your ear using one hand. This should be very useful for pedestrians and drivers.
The environment in which I use the headset is pretty tame without loud noises or vibrations.