Inconsistent sound quality.
I bought this to pair with my wife's cell phone but she didn't like it and gave it back to me. She said it didn't fit her ear well and the sound quality was bad. I paired it to my cell phone and some times it was great but other times the sound was awfull. I now use it just for Warhawk on PS3.

More volume, please!
It functions okay, but I find that I can't get it loud enough in noisy situations like an open car window, or the manufacturing floor where I work. Also, people I talk to tell me I have that "tin can" sound. I also get a lot of static. My son's Jabra works a lot better. I'm running this with a Motorola Z3.

Bad battery life
Was disappointed to find that this headset had very poor battery life. Longest time it has held a charge without having to be re-charged is 3 hours.

Dave A
Great product for the price. It works well, and beats using the wired headset that comes with most phones. Motorola headsets are a plus for people with Motorola cell phones that use the USB wall charger because the headset comes with the same wall charger, so you only need to bring one charger for both devices when you travel.

Too little juice
There are good things to say about the H350. It is light and simple to use. I liked the flat ear piece and found the ear attachment loop to be convenient.
However, it simply doesn't hold a charge long enough to make it worth purchasing in my opinion. I can't rate it more than a 2. I also have the Plantronics Voyager 510 in the car and it is well worth the extra money. The last thing about the Motorola H350 is that the lack of a boom makes it just a little inconvenient for people to hear me.
It isn't a horrible product, but limited battery power is enough to make me return this.