I have smaller hands and I can't get away from interlock. The overlap doesn't feel right with my strong grip. If I had to pick a second favorite, it'd be what you call a double interlock. Tiger used to use that grip, putting his left index finger between his right middle and ring fingers.
I have always used an interlock. One of my friends is new to the game and was using a baseball grip - I changed him to the proper grip with which he was most comfortable (interlock as it happens) and it made an absolutely incredible difference. With the baseball grip there was a tendency for everything to become disconnected with the right hand taking over, change it to a proper grip and the swing is inherently less able to do this and this I guess resulted in the increase in quality of strike and level of control.
I learned to play as a child w/ an interlocking grip, but my first golf coach changed me over to the Vardon grip around age 13. After dealing w/ the "discomfort" of the new grip for a couple of days, I never looked back.
I use 8 finger grip...its the ten finger grip with the right thumb and index finger just riding on the shaft...I don't curl them around the club...I found that leaving those 2 fingers loose I avoid too much grip pressure on the down swing...
I'm a left and I use what I guess you'd call a reverse overlap. I overlap my right index finger over my left pinky finger. This has always been my grip for putting and chipping, but a couple months ago I switched to using it for everything else from an interlocked grip and have been much more comfortable with it.
Surprising result to me as well, I thought most folks used the Vardon overlap.
I have small hands, and the interlock just always felt like one piece for me. With the baseball grip (elementary school, my first 3-4 years of playing), I feel like my hands are working against each other.
A lot of folks have told me the overlap feels unnatural at first, but once you commit to it, that goes away. I guess after 35 years of interlock, I am reluctant to change.