My buddy just got a 10s and the other day we went riding to see how well the 20s and 10s played together. The intercom pairing was quick and easy, and clear as a bell with good distance. It also seemed like it kept working when a few cars got between us to block line of sight, which was something that was a problem I had experienced earlier with two 20s's.
One thing we did notice which might not be apparent to potential 10s buyers was that intercom conversations had to be manually terminated on the 10s for him to resume listening to his music player. He had to tap the jog dial for his music to come back up to volume, whereas on my 20s my music resumed when the intercom conversation stopped, something it does automatically with no button tapping necessary. I could also tap my jog dial to end the intercom conversation manually. It seemed either of us could do that, but for the 20s it was not necessary.
So besides features there is a difference between the units but this was not something you'd ever think of until you experienced it first hand with use.