Definitely two crates. It's not such an issue with puppies, but from adolescence onward, I think it is better and safer to crate your dogs separately.
I don't personally believe that being crated together will have the slightest impact on how much they bond with you versus each other (actually, I think that's a bit of an old wives tale at the best of times

). But as they grow up, they do need their own space. Primarily it's a safety issue - should there be a disagreement in the crate (quite likely if you also leave toys/kongs/food to keep them entertained whilst in the crate) then there is nowhere for one dog to back off to and a minor disagreement can easily escalate into a full-blown fight. And still no way for one dog to back off...
IMO it's better to be safe than sorry, and you can always crate them right alongside each other for company.