NOT the same action. I unless you're using an elaztech plastic or other floating worm, the bait trailing a carolina rig is dragging behind the rig on the bottom. Its simple physics. It doesn't "float up" above the weight; thats nonsense.
A drop shot bait is suspended off the bottom, and can be wiggled in place indefinately.
I prefer the drop shot, and I often drag it like a carolina rig. However a carolina rig is better for covering deep water quickly. Both excel at feeling bottom composition.
As for your question: it depends. if the fish are scattered across a 15ft flat, I'd toss the c-rig. however, if those fish are relating to vertical structure, or if they're in a specific area, drop 'em.
My $.02.