Pros: I sought out the Plantronics M20a after trying on a friends. I was tired of the inconsistency and clumsiness of my Jawbone. After hitting three ATT stores, I found it online for nearly half the cost., about $20 out the door. Initial pairing was a breeze. It holds charge as well as expected, and is quite comfortable to wear. My ears are large; my friend's are small.
Sound quality is okay. The volume adjustment on the phone is extreme, but my phone lets me adjust more finely.
Cons: I have a lot of lost pairing, difficulty pairing and dropped calls. Part of this is due to clumsy fingers--there are buttons on the top, front, and side--so adjusting the set in my ear leads to unwanted hang-ups. Part, though, is the electronics. Often, it takes several attempts to pair. I find myself turning the set off and then on, and digging into the blue tooth menu in my phone to get connected.
Still, pretty good for the price.