There is a bit of a learning curve to road bikes. The handling and the position are different. The gearing is likely different too, so it takes you and your legs a little time to get used to that. You'll probably feel faster. The thing with hills is that a hybrid/flat bar is likely to have lower gears than the road bike (which has "go faster!" gears), so you may feel that it's initially harder to climb on the road bike. Compact doubles feel weird to me, but that's probably because I'm not used to it (I have a triple).