I have the SMH10-11 ... It has been one of the better moto related purchases that I've made. Now mine doesn't have the FM radio feature, but the other stuff is probably the same or similar.
The one friend that I ride with on a regular basis has the matching unit to mine, and we like the functionality of the bike to bike intercom. It is easy to use and has good range.
The ability to make phone calls via Bluetooth is equally nice. It makes keeping touch with family while on long road trips much easier - and it's nice to have someone to talk to on the more boring stretches, or when you are getting tired.
Since we've owned ours, Sena has been fairly consistent with the firmware upgrades, and generally seems to have good product support. The latest upgrade allows for music streaming from user to user - COOL! We haven't had a chance to try that out yet, but I'm sure like all of the other features, it's gonna work well.
I have my bike setup so that I can charge the system while I ride. It works great. The last REALLY long trip I took was 22 hours from Houston to San Diego - I had no problems with the setup.
Ride in the rain? No worries, the Sena will perform.
Now I haven't hooked up a GPS to mine, I pretty much use an iPhone for everything, so I can't comment on that.
The only thing that I wish they would address - with a real, valid solution, is the fact that the music volume is pretty much useless at highway speeds. Phone and intercom volume seems to be fine, even at high speeds, but the music washes out after about 50 MPH. There have been those odd occasions when the wind must have been just right, and I was able to enjoy the music up to 80 MPH or so. But make no mistake, those are rare occasions.
With that said, be aware that I am one of those guys that rides with foam earplugs. So I'm protecting my hearing, but at the cost of lower perceived music volumes. Also, I should mention that all of these impressions are from use in my Shoei Qwest. The Qwest has a chin guard standard, and I am sure that it helps reduce some wind noise.
Recently I discovered and purchased a set of Tork X Pro helmet speakers and a Tork portable amp. I installed these in my helmet using one of Sena's mounting bases that is made for use with ear plugs. The sound is improved. There is more bass response, and I can usually hear the music up to about 80 MPH on a consistent basis. The drawback is that I now have extra stuff to wrestle with when putting on my gear - and something else to charge (the amp). Was it worth the additional $100 I spent? I don't know, I'm still undecided. Is the sound quality improved enough that I would agree with the folks that say that the X Pro speakers provide 'concert hall quality' sound in your helmet? No, I don't think so. They sound ok, but the reviews I read before I purchased mine hyped them up so much that there's no way they could have lived up to my expectations. The X Pro's are a bit larger than the Sena speakers too, so they don't fit into the speaker depressions inside my helmet as well - they touch my ears, and necessitate an extra bit of helmet adjustment after I have donned my helmet.
So what's the point of all that? Just this. Sena puts out some nice products, but it's rare that any product will be perfect. Sena does seem to be one of the leaders in helmet comm innovation though, so I am looking forward with the hope that eventually they will make the kinds of improvements that I am looking for.
(OH! And, I read that they have something AWESOME in the works that will allow Sena users to communicate with folks that have other brands of helmet comm systems. COOL!)
