I bought this thing primarily to use in my helmet while on teh street bike (full face helmet), and after modifying the earpiece that goes into my ear canal (stock unit doesn't do this), it worked ok, though i could hear the other party on the phone perfectly while on the freeway, i was muffled at even 50mph, though they could hear me. the unit worked over 30 feet line of sight away from teh phone (nokia), i havn't had any interference with it, and it is relatively easy to use. there is no indication on how low the battery is, though it lasts decently and to turn teh unit on and off, it pretty much can't be nestled down on your ear unless you enjoy pain. the behind ear look and feel is decent, though a person with smaller ears will probably have more problems with a proper fit. the 3 ear pieces that come with it create excellent sound quality, but wearing the unit with these for extended periods (3hrs+) resulted in my ears aching some. the new ear pieces dont do that, i made them from the rubber ear pieces like those from fontopia earbuds. i cut one of the stock earpieces apart, and superglued the earbud into place, then stuffed some foam down the middle of the canal piece as its too loud in the ear otherwise. sound quality is notably lower, but its lower profile to my head and so it fits in the helmet better. beyond that, i have had no problems, people can hear me fine adn I them. i have had no problems getting the phone to connect to it as long as its done in the right order. (phone on blue tooth, THEN ear piece) over all i am happy with the unit. it does tend to want to fall out of my ear when i'm upside down, and a little bit as well whem i'm running hard or extremely active...though with a stocking hat its ok. don't forget to charge this thing all night the first time through. it will help with battery life. full 24 hr charge 1st time, then full discharge and full recharge first 3 battery life cycles for maximum battery life.