I was looking at these a while back, both of them in fact. I decided the Sena ones would be better because of ease of use. You can leave the link open so you can talk freely without pressing anything, which you wouldn't want because of the singing bit. Or you can press the jog dial for a brief moment to initiate communication then talk, I understand this to be the best way to go with these. The Sena seem the simplest to use on account of having just the jog dial to worry about.
The Scala ones are better if you ever plan on adding multiple users to the ride as you can communicate with up to 4 riders simultaneously, the Sena let's you talk to only one rider at a time. I understand this may change in the near future with software updates however.
Anyway, check out Advrider, they have some great threads going on both and the Senas can be had from a dealer offering really good pricing to folks on the Advrider forum.
For the record I don't own these yet as I'm still undecided about going with a new Autocom setup which will be significantly more expensive, or with the Sena's which can be had for $280 for the pair.
Last edited by l84toff; 12-20-2011 at 01:24 PM.