+1 % hit = +1 % dps

- up until you hit the cap - 18 %

Dualwielders:
+18 % needed for main hand
+24 % needed for off hand

- Off hand does less damage than main hand. Which means that from 18 % on, you won't be getting the full +1 % dps for every +1 % hit.

But:
- Rogues have up to +50 % off hand damage from talents.
- Warriors have up to +25 % off hand damage from talents.
- Shamans don't have this talent.

Basically, +hit is the best way to increase your dps until you hit the cap.

There's a reason why you see some pro rogues with 2-300 hit rating or more, if they can get their hands on more. That, in addition to maxing out their +hit talents of course. +hit for the win.