Hi, I actually had the three of them installed on my 2007 1100 Hyper.
- The standard seat is 20mm (less than 1") higher than the comfort and racing seats.
- The comfort seat has a gel pad that makes it softer and reduces the vibrations (you can ride for more miles and still love it!). With this seat the riding feeling is better than with the stock seat because you feel more "inside" the bike.
- The racing seat is made to let the rider move from one side to the other very rapidly thus is very hard. The look is better than with the other models but it may become very painful on long rides.
I'm currently using the racing seat because I ride in the hills around the Mugello area where the longest straight is maximum 1 mile, so on winding roads I have always to move on the seat.
I never reach that point where I have to stop due to the pain on my back or bottom.