The question of how a DB press compares to a BB press is frequently asked, and I think that they really don't cross over in anything more than the most general sense. I don't think you can train DB to get your BB up, and you can't train BB to increase your DB. This probably has a lot to do with those stabilization muscles limiting the carry over. Moving from DB's to BB you probably have not used enough weight to really battle anything significant on a BB. Going from BB to Db you have neglected some of that feedback that DB's require in order to maintain balance and an equal rate of press out of both arms.

Given the option, I would say that I would prefer to have a set of monstrously heavy DB's. I think that the application of DB's to sport or athletic undertakings is probably better (assuming you could get HEAVY Db's and you wouldn't be holding back your strength progress by using them).