On the surface this is an improvement over the previous version[s], one noticeable difference is the length of the microphone attachment, making it easy to fit to a flip-faced helmet, where the mounting needs to be a little bit further back, so that the lid can be closed without obstruction.
Attempting to connect various devices is where the major disappointments are. I could connect TomTom Rider V2 OR my iPhone 3G, one of them at a time only, and had to reset to factory settings the TomTom a few times in the process - otherwise I kept getting a message that the headset was not connected. When the iPhone was "successfully" connected, the microphone was next to useless - the other side couldn't hear me at all, while I could hear them loud and clear.
Tuning the radio to the desired stations is no easy task either, which left me wondering - how difficult could it have been to provide a USB connection and web interface of some sort, that would have made all this so much easier.
One other thing - the right hand side earpiece seems to be noticeably quieter, but that may be on purpose.
I haven't attempted connecting to any other Q2 devices, but I'd loathe to have to reset my TomTom yet again, given the fact that SatNav was the main reason (radio - secondary) I got the device in the first place :-(
All-in-all, if you must get a Scala Rider with a radio, get the previous version - it's £30 cheaper!