I feel turned off by the whole idea of them right now, but I’ll need to let it simmer for a while and do a lot more hands on testing. The big question to me is: why?
So you can now code with a bunch of divs and have it behave just like a table. Why not just use table tags instead? Because they are div’s that is somehow better code? It’s still source-order-dependent and requires you to re-define all the display properties of all those divs. Where is the true advantage?
As an aside, they aren’t supported in IE 7, so it’ll be many many years before they can be widely used anyway (not that that should be an argument against them).