I tend to go for the cheap v6 bluetooth on eBay it's £30sound quality is decent battery life is amazing connects well to your phone connects up 5 riders and if you get a call it automatically answers pretty decent bit of kit and if you should loose it, its not so bad as its only £30
after reading different reviews and seeing lots of YouTube videos I'm going for the Cardo Packtalk Bold as it allows up to 15 riders to come in and out on the mesh system plus it has Bluetooth for calls navigation and music not that I have that many friends who i ride with but most reviews say to stay away from Senna I know most off them are over priced for what they are and do but best to stay mainstream otherwise your have that problem linking up with other riders
I have used Sena for about 7 years and never ever had a problem with them, its just a matter of choice, I have linked my Sena to many different makes in the past and it has always well, never had a problem with it.
Kendog It depends what you want. If you just want rider to rider the v6 is good but if you want multiple rider then not so as you have to switch between. For multiple rider get a network set not cheap but worth it