The key is "noticeable" differences in "performance/handling" -- the short answer, imho, is "none". As it happens, I prefer the look of compact frames, but that's by the by. An elite-level pro rider might - MIGHT - notice the alleged advantage in stiffness that some companies promote, but I can't see how most of us could. Other than that, what difference could there be, all else being equal? Fit at the contact points, and essential frame geometry (s/a, h/a, rake, trail) have no correlation to a sloping or conventional top tube.