If you're in the market for a communicator to add on to your helmet, the Sena units are a pretty good option. But which one to pick?
SMH-10 vs SMH-10R vs 20s
I started out with an SMH-10, which served me well. It does what it says on the box with few problems. It takes a bit of practice to figure out how to get everyone paired up, but usually there's no need to mess with it again after everyone's paired and the units reconnect automatically. The couple of pain points I had with the SMH-10 were:
1. I kept hitting the jog-dial accidentally with my shoulder when getting on/off the bike.
2. Sometimes you'd have to jostle the unit a bit in the mount to get all the pins to make contact.
But really, no big deal.
When I purchased a new helmet I took the opportunity to upgrade to the 20S. I'd say that so far I haven't really found it to be worth the difference in price. There are only pros, versus the SMH-10, but the're not huge ones.
1. I less frequently the jog dial by mistake, but it's still possible.
2. I haven't had problems once it's in the mount, though it is a bit trickier to get the unit mounted while your helmet is on.
3. Noticeably better battery life is nice.
4. The built-in FM radio is a nice convenience, but not essential.
The "meh" of the 20S:
1. Supposedly you can overlay two audio sources at once, I've found this to be either useless or unnecessary in most situations.
2. It supports paring with up to 8 people, but you'll apparently suffer a loss of quality if you enable that. I don't ride with that large a group, so it stays off.
3. Supposedly the range has been doubled, but I never had a problem with the range of the SMH-10.
4. The voice control is iffy, and the button on the bottom of the mount is hard to hit with gloves on (tapping on the unit is supposed to also work, but rarely does.)
So basically the advantages to me are longer battery life and I don't hit the jog dial as much. An improvement, but not worth the difference in price. It seemed like the app might offer more control/customization of the unit through a better interface than the two buttons plus jog dial could offer, but mostly I just ended up using it to review the documentation for obscure features like trying to join a phone call into the group intercom. Perhaps the app will be improved in the future with more features. Sena appears to release firmware updates regularly.
When I upgraded to the 20S I passed down my SMH-10 to a friend I ride with frequently. He has subsequently also purchased an SMH-10R for his other helmet. He recently posted this review:
"I felt the need to upgrade and get a second sena comm unit for my fleet of helmets. I got the smh10r off Craig's List for a reasonable price. First impression, this is a permanent attachment and not transferable like the smh10. Lots of cables to hide and a remote battery pack to mount on the exterior of the helmet. Honestly, I would rather had another smh10 to clip in rather than a second battery for this slim line model.Pros: it's slim as hell, but not too small to be a pain to use. Also, no fear of knocking it off mid corner.Cons: wiring nightmare. Attaches with lots of double stick tape. My smh10 had a clamp on mount and a boom mic, it was pretty easy to swap from one helmet to another. The smh10R.... I'm not moving any time soon."
My cousin also picked up the SMH-10R and had a similar experience with "wiring hell". However, it otherwise seems to perform just as well as the SMH-10. On our first ride we inexplicably had an issue where it kept going in and out of intercom on its own, but after about 15 minutes the problem went away and has never resurfaced. Also worth noting is that with the SMH-10 or 20S you can remove the unit from the mount and charge it on your desk. However, the SMH-10R doesn't detach easily for charging.
All in all, I think the SMH-10 is still the best bang for your buck. The SMH-10R is about the same price, but you have some trade-offs for the slimmer profile. It seems like not being able to remove the battery and charge it separately from the rest of the helmet is a design flaw.