What to expect 'quantitatively' is pretty straightforward, and helpfully tabulated at the following link: difficulties thread on civfanatics
'Qualitatively', though, I have to say that the game becomes a lot less enjoyable on higher difficulty settings. That's because 'higher difficulty', in this game, is a matter not of facing smarter rivals, but of having to withstand the computer endlessly SPAMming every possible resource, and throwing them at you.
I can (barely) attain a science 'victory' on Emperor, but most of the time it's pure bloodbath against enemy hordes.
'Qualitatively', though, I have to say that the game becomes a lot less enjoyable on higher difficulty settings. That's because 'higher difficulty', in this game, is a matter not of facing smarter rivals, but of having to withstand the computer endlessly SPAMming every possible resource, and throwing them at you.
I can (barely) attain a science 'victory' on Emperor, but most of the time it's pure bloodbath against enemy hordes.