I have no experience with Cardo, sorry. I have the Sena S20 Evo, and I usually ride alone, so I haven't even tried it's bike to bike capabilities, but it works great for phone and I love it's FM radio. I use it commuting and get the local traffic updates, and the sound is really good. Much better than my old S10.
Havenít tried the latest Fredom range but Iíve had the early Scala Q1 for about 4 years now and itís been very good. It still lasts all day on a charge and Iím either play music or listening to the radio all the time. I also have the sat NAV connected on long journeys and it switches between radio, music, phone and sat NAV seamlessly.
Iíd buy another one when it dies