what is it about Rebels and Patriots that makes you like it so far ahead of its siblings?
I like them all, but have played R&P most. It gives (me) an enjoyable
game. I don't spend most of the time with my head in the rulebook.
I do find myself looking at the nice figures & scenery on the table,
while actually thinking about tactics. What is my opponent thinking
of doing? What do I need to move, shoot, rally etc. in order to
frustrate him? Can I afford, for example, to leave my left wing to
get on with delaying him, or had I better rush re-enforcements over?
Subtle differences do (I feel) add a certain period flavour,
R&P = Horse & Musket, LR = Medieval & DR = Fantasy.
Plus all of them will survive the addition of a few house rules.