CnD more suits my playing style and i think that each 'watch' comes with a fairly well defined playing style.
Don't get me wrong, you could quite happily use any of them for any situation, but there are sometimes when one would make more sense over the other.
From what I've seen:
> CnD - deep operations. Can get well in behind advancing enemies and stay hidden, striking at high value targets.
> Normal - Just in behind the front-line, most versatile, most people know how to play this one anyway.
> DR - not tried this one yet, but most spies seem to be quite happy to run around with the ambassador, firing wildly at an enemy, 'die' and then re-appear right behind their target.
Either way, i'm sure everyone will play with whichever variation they find most suitable.