Summary: I recently just purchased a LG 325 bluetooth phone for use on the Sprint network. Originally I picked up a Sony HBH-600 because that was the only headset that they had in the sprint store. I drive a Jeep Wrangler and regardless of what top I have on the Jeep, soft or hard, there is a significant amount of road noise present at pretty much any speed. It didn't take long for me to realize that the HBH-600 was not going to work. Callers complained that they couldn't hear anything I said and when I turned the volume up to a level that I could somewhat hear, they complained that they then heard echos. So began my search for a good bluetooth headset that would work in the Jeep. I purchased a Jabra BT800 and was not satisfied with it at all. Cheap build quality and inferior sound led me to keep looking. From my research I narrowed my choices to the Plantronics Voyager 510 and the Sony HBH-300. No where around me carried either of these headsets so I had to order them on line. I found the Plantronics for $38 and the Sony for $70. Both have excellent build quality, they feel like they would not break if were to drop them. Callers have reported that both provide excellent call quality. I have though, decided to go with the Plantronics Voyager 510 for the following reasons.
The Plantronics feels extremely comfortable in your ear. At times I forgot that I was even using it. In the package you are provided with three different sized speakers that easily attach to the headset. At first I didn't think I would like this headset because I find that stereo earbuds that are inserted into the ear canal to be uncomfortable. The plantronics, however, do not insert into the ear canal, like some jabra headsets, but instead sit comfortably in the ear. Because of this it also provides better volume, I actually had to turn the headset's volume down while driving because it was to loud (and this is in a Jeep!!!) Callers rated both headsets equal in quality on there end, with maybe a small nod to the plantronics headset, a few callers said they could hear that pesky echo again with the sony. The plantronics headset is also much easier to cary on your person, the boom swivels up and the earpiece rotates to make a nice, small, flat package that can easily be placed in a case on your belt, the sony, however, has a non-collapsable boom and because of this is quite large. In the end the excellent build quality, voice quality, sound isolation, and value (only $38), made this the headset for me. Highly recommended.

Summary: After trying both high-end Moto and Jabra models, I decided to go with this one. People couldn;t hear me on the Moto, even when i turned the input level to max. I couldn't even get the Jabra to pair up with my Mac. The 510 worked right out of the box just as advertised. Works great with my cell phone, Skype for Mac, iChat, etc. Definitely recommend this.

Summary: Based on Laptop Magazine review, picked up this unit (my first ever Bluetooth headset.) It is comfortable, and the sound quality is high. I do wish they would would have designed the on/off control as a slide switch, having to hold down the very small button for three seconds is a pain. Overall though I am very pleased.