I've only had a little bit of experience with what I thought were just called "square drive" screws. I think that their greatest asset, that it's nearly impossible to have a power driver bit slip out or strip the head, can also be a minor drawback. They hold the bit SO well that they tend to pull it out of the magnetic bit holder in my drill. I suppose if I just got separate (longer) bits that go into the chuck directly I wouldn't have this problem. With today's keyless chucks that might not be such a bad thing, I suppose.
I usually use phillips. With the aforementioned magnetic bit holder I find it pretty easy to start them at any angle also. Their lesser bit-holding ability only becomes a drawback where there is a great deal of resistance to turning the screw. Maybe next time I buy drywall screws I'll get the really long ones in square drive.
Greg Guarino