Vanilla has less maps, less bricks, and less features. Every once in a while, yeah, I like to build old school... but really, Vanilla? What the hell? I suppose you could play it for nostalgic purposes, but that will tend to get boring IMO. I'd probably just play RTB with the map on Bedroom, no wand, no special admins or player functions, no floating bricks, and no build through bricks. Realism, basically... but then again, I guess it doesn't really give you the same feeling that Vanilla does... Vanilla's more challenging and brings back memories...
Meh, dunno.