I purchased this headset as a replacement for one that I lost (same model).  Prior to purchasing, I tried a number of the Motorola headsets and found them to be too loose on the ear.  The Plantronics 330 fits comfortably snug.  Sound quality is good, volume is adjustable from soft to loud, and those on the receiving end hear me clearly.  The command function is nothing short of remarkable; simply say the name of someone in the phone's directory and it gets it right 95% of the time.  Dialing by verbally calling out the numbers is equally accurate.  I highly recommend this headset.