I have been using my Sena SMH10D-11 for a few weeks now and just love it. The sound is clear and the controls are easy to use. I can adjust the volume up or down with my Tourmaster gloves on or even skip ahead or back on songs when I pair my smartphone to it. The battery life seems to be quite good as well. One day I was listening to music while riding and I started to hear beeps go off. I thought '"what's that?" and then thought it might be someone trying to call my phone. So, I said "Hello", and the Sena SMH10 answered. It was my friend calling me. He said he couldn't tell I was riding a motorcycle. The sound quality was very good - using my full-face helmet. I will say that playing music lacks good bass but is still pretty good. You can't expect much from such small speakers. They're not like earplug style speakers. Voice quality (send & receive) is excellent. Installation was pretty easy on my full-face helmet. Just unsnap and pull out the liner panels and run the wires through it, then snap everything back in. Took about a half hour for each helmet. I did have to cut a notch in the plastic edge molding on the helmet next to where I mounted the Sena to make it easy to keep the it's wires close to the edge. The "11" model is the way to go for full-face helmets since you get an additional mic that can be attached just in front of your mouth on the chin guard with the Velcro strip provided. You also receive a boom mic if you need to attach it to a 3/4 or 1/2 helmet.Just a word on Sena's Technical Support folks...(since some reviews have entered negative comments regarding Sena's customer support). I emailed them (Tech Support, not Customer Support) before I made the purchase because I had questions regarding the differences between the SMH10D, SMH10D-10 and SMH10D-11 and also how to interface with the CB radio on my '05 Harley Ultra Classic. I received an email back from Tristan right away and he and I exchanged several emails until I had all of my questions answered. Tristan went above and beyond to help me. So, I'd like to give a little praise where praise is due. I was a bit disappointed to learn I would not be able to talk through the additional SM10 transmitter (in conjunction with the 7-pin DIN connect cord they sell) on my CB, but I could listen to it - and the FM radio as well. I told him it would be great for Sena to add that feature and he said he'd pass it on to their engineering department. So, I'm hoping something happens as a result of that.I ordered the SM10 and interface cable today. So, once I have that installed and working I'll review that as well. Once again, great product - and looks good too!