I think that as the year goes on, we'll find a lot more towns available for download as players get used to Create-a-World. I recall from an interview that testing out a world for playability can take months, so it's still a little early for lots of choice.
By the same token, before downloading a third party town, it's probably a good idea to check out any possible reviews for it, so you don't settle in with your family and then discover that it's impossible to do X, Y or Z. Obviously, it's also this forum's policy to recommend against any third party content, because you can't be sure what bugs it might introduce to your game. But I would just be extra careful with towns, because none of the customisers and modders have experience with making those yet.
I suspect that because they've released Create-a-World, there won't be any more EA neighbourhoods to download... the effort that goes into building one is probably not worth it for them. I kind of wish they'd configured the towns in World Adventures so that they could also be functional neighbourhoods, but sadly not.
