Cannondale's site is down...

[OakLeaf]

I don't really have anything to compare it to, but my '07 Synapse feels fine on descents and corners. I think I've maxed out at 47 mph on a descent, so if you have longer hills than we do here, I can't say how it might feel at higher speed. OTOH, when I ride in a group in the flatlands where everyone else has fancy expensive race bikes but no one has any cornering skills , if I'm pulling through a corner, I can pretty much count on having to wait for them to catch back up.

What tires do you have on yours? Tires make as much difference in cornering as frame geometry does, though they probably don't affect downhill handling that much. I just love the round profile of my Conti GP4000s.

A curved fork reduces handling

Well, not exactly ... it's a balancing act, like most things in frame design. A bike that twitched every time your heartbeat came through your hands wouldn't be considered very good-handling either. Rake and trail act together (along with wheelbase, steerer offset, etc., etc., etc.) to give you a chosen balance of stability, comfort and responsiveness. And in the two things we're talking about - a more stable bike will feel better on the descents, a more responsive bike will go into the corners quicker ...