I had a Mustang seat on my Suzuki C50 and it made a world of difference. At this point I don't have any issues with the F6B seat (have only done 250 in a day and that was 125 - 2 hour break - 125) but I do wonder about it in the long run, also I like the looks of the Mustang better.
I do share part of Scotrods concern, while I wish I was an inch lower from the perspective of being able to flat-foot the bike comfortably I am not big on the idea of having an extra inch of bend in my knees. I am thinking that maybe the Mustang seat with the Kuryakyn pegs that give a 3/4" drop might be the way to go, although chances are it is an upgrade that will have to wait until beginning of next year so I will be watching for reviews if anyone else decides to be the forum guinea pig.