I started out on a Honda F3, and found it to be a great beginner's bike, never gave me any handling or power trouble. I have never owned a Kawi before the 03 636 so I can't give great recomendations on those. All bikes are easily uprgradeable for cheap, so you won't get sick of them fast. I hate R6's for beginners bikes because they are notorious in my experiences for too easily tucking their front tire in comparison to the others. Go for the 6R or the Gixxer, not much diff except for looks & small ergonomics.