I got in on the kickstarter with both the urban streets and rolling fields themes, I really like both, but for different reasons.
Personally, I don't think the urban streets set would work very well for WW2; it's far too modern looking
IMO. You could probably make it work with the right paint scheme and using enough terrain to draw focus away, but I personally wouldn't. Another thing to keep in mind, urban streets is pretty firmly in 28mm territory in terms of scale, so if that's what you'll be using then fair enough, but personally I like 15mm for historicals so it's less suitable for me. Another consideration I suppose, is do you want to be playing in a city every game?
The rolling fields theme, on the other hand, is
IMO, far more suitable for historical games. It's both scale and period neutral, so will happily do anything from Roman to WW2 and in a bunch of different scales, and I think it's far more flexible.
So I suppose in summary I'd definitely recommend the tablescapes, they fit together nicely and are quite sturdy but you should definitely consider the rolling fields theme if you're playing historical games.