HI,
I bought an airhawk (the cheaper version) a few years ago to put on my BMW R1100GS that I had at the time. For short runs, the GS standard seat was okay, but after an hour or two, my rear end began to suffer. The arihawk cured this, once I'd worked out how much to inflate it. You dont need to inflate them that much.
The only issues that I had with it is that it obviously raised the seat height on an already tall seat, which was a little unnerving at times. You do wobble about on it a little as well, when you shift your weight, due to the air moving between the smaller air pockets within.
For a cheap alternative to sore a**e syndrome I dont see how you can go wrong. If you were nearer, I'd say you could borrow it and try it out for a week or two.
Good luck with whatever you decide to do.
Cheers Skid