Advantages of running flatslides?
 

A buddy of mine came across some 35 or 37mm Keihin flatslides, and I really don't know the difference other than racing bikes use them. I've read of people running them on the street and some love them, some hate them. Can anyone fill me in on these? They seem like a good price for $200, but I'm not sure if there's any point in gettin them. My bike has:

'98 F3 engine built to 637cc 13:1 compression
Full exhaust
Working on a ram air setup to use with my f4i upper.