I've got a few of each.
Here's what i like and don't like about each.

Leathermans
Dislikes--can dig into hand when using pliers with force
can't open it with one hand (pliers)
Likes--better blades

Gerber
Dislikes--can pinch hand is pliers slip
metal in blades don't hold an edge
Likes-- You can open it up with one hand

I tend to take the tool depending on the job I antisipate. If I'm out mending fences there is no dispute...Gerber You can hold the wire with one hand while retrieving the tool and getting it out to be used while still holding the wire. If I think I might be cutting anything, the Gerber stays in the truck and my leatherman is with me.

I'm sure there are some other peoples opinions too.