Personally, I was fine with ditching tables, but stuff like differing box models, unequal CSS support, quirks modes, etc did make for a rather painful cross-bro

Personally, I was fine with ditching tables, but stuff like differing box models, unequal CSS support, quirks modes, etc did make for a rather painful cross-browser development experience: Making things work out correctly (or at least gracefully degrade) in multipe IE versions, Mozilla, Opera, ... could be a challenge.