I've got one. Much more comfortable to ride. Will vouch for fact that you must have the pillion seat (or at least some of the original bracket) to use it. Currently, I have an "un-upholstered" pillion seat as a "luggage rack".
Be prepared to wait a bit for it to be made and shipped. The order form will point out that it will not be manufactured until DATE XXX. I appreciate that the guy tells you up front, rather than taking orders and dealing with the complaints.
For those of us with less-than-ideal posture...it's a must have.
MarvinM