I use the Chatterbox FRSX2 setup. I don't have any experience with others to compare to, but have been happy with the performance so far. Bike to bike or with pillon rider its worked well! The speakers are good and the ability to pip in tunes (and even my cell if I want) are a BIG plus, but I beleive all the major companies have the audio in capability.
I did hear that Chatterbox was coming out with a Blue Tooth version this fall, but that was earlier this spring when I read it on a board somewhere. If thats the case, you get rid of the wires and open up possibilities for GPSs, Cell phones and with adapters radar detectors. Blue tooth is gonna hit the US bigtime in the next 18 months. If you don't already have a BT compatible gadget, you will!