Where did you see the 10ft limitation? All the manual says it range might be less than regular Sena-to-Sena intercom, depending on the device connecting. To me, it seems more like the weak link is whatever you are paired to, so maybe 10ft if you are connecting to a BT earpiece like people use in their cars, since it has a smaller/lower gain antenna.
As for Sena vs Cardo (Scala), all I'll say is Sena has been extremely good providing firmware with new features into their existing product lineup, where Cardo and others seem to release new models instead. That's a big point towards Sena in my books.