I've used the 10 finger grip at times - first tried it after a minor injury to my left forefinger, which made my usual interlocking grip uncomfortable. It was a surprisingly smooth transition between the two grips - a slightly different feel to the club releasing during the swing, but I found that I could hit usable shots pretty much straight away. (It seems a little bit strange that I'm comfortable with both 10-finger and interlock, but an overlapping grip just doesn't feel right to me...)
For what it's worth, I use a slightly unorthodox grip for putting - standard left hand high, interlocking (right pinkie/left middle finger) with left forefinger down the outside of my right fingers. It probably isn't in any of the manuals, but I'm comfortable with it and usually putt pretty well...