Ashlynn Brooke may be slightly better looking. But I am not sure there is anyone who is a better sexual performer than Madison Ivy right now. I have always been sort of lukewarm on Ashlynn Brooke's performances. I don't know why but she always struck me as on of those, "I know I am ridiculously hot and you should just be glad I am fucking and you get to watch" kind of girls. My least favorite kind of performer.
If I could spend a weekend in bed with any pornstar right now it would be Madison. Watching her fuck is mesmerizing at times.