Love my Sena 20s, only real complaint is that the battery is non-replaceable. When it fails you have to replace the entire unit.
I managed to squeak mine in on a warranty replacement, and Sena did eventually replace the unit, but they dragged their feet on it for quite some time before making good on it.
(I've read there are some ways you CAN replace the battery, but it's not a simple procedure.)
https://www.youtube.com/watch?v=PF2dH05nzDgBatteries are replaceable...
I replaced the batteries in my Sena SMH10's with a slightly larger battery off of Ebay after finding how on YT. The tec rep I called from Sena after they died just after the warranty ran out actually gave me the link! Longer lasting, and was easy to do. The originals last just before or just after the warranty runs out on all Senas it seems, but at least now they're not just a disposable item with these other batteries available.