Thought I'd chime in. My wife and I have the Sena SMH-5 which we use for bike to bike comm for the past 3 seasons.
They are sufficiently loud enough for our needs and since we only use them to talk, the dynamic range works well higher
frequencies seem able to penetrate wind noise better.
They are good up to about 1/2 km (give or take) and as long as you have direct line of sight.
We only ran out of power on them one time, and that was about 6 hours of riding.
My only complaint is that you need to maintain the batteries in these. Mine completely discharged while in storage and I couldn't revive them.
Sena will not replace/repair them once the units are out of warranty and do not supply batteries, so you are on your own to find suitable replacement batteries.
There's a fair amount of chatter about this on their forums.
I found a source from a robotics kit supply company in Vancouver (under $20 taxes and delivery included) and only had to solder the connectors from the original batteries onto the replacements.
Again that's my only complaint, now I make sure to top up the charge every month while not using them.