Worth it to buy an unlocked Galaxy Nexus?

I'm considering importing an unlocked G-Nexus from the UK but I'm not sure if it's going to be worth it.

If I get an unlocked G-Nexus and put it on T-Mobile unlimited (which sounded good), I'll just get throttled. If I put it on AT&T I'll have to use data caps..

Their's probably something I'm missing here but what would be the benefits of buying it unlocked?