I've been using this headset for about two weeks with a Blackberry 8700C. The headset has a very comfortable fit and the volume is nice and loud. The downside is that the battery life seems a bit sub-standard. I have been caught several times using it and running out of batteries. I also have some random disconnects with my Blackberry. Tough to say whether these disconnects are phone or headset related. I think this is a great value for the money though and prefer it over the Motorola's and Jabra's (better fit, louder sound). There is some difficulty pressing the buttons on this headset too - nothing that I could not work around though.