They both essentially mean, "well done". Only Australians say, "good on you". If a situations deserves a, "well done" people say, "good for you" (in Australia they say good on you) but if something has a health benefit, like vitamins, THEY are good for you. It can also be used for financial advice, "if you change from one bank to another, and you get a higher interest rate on your savings, it would be good for you". (ok, arguably, "better for you"). Simple answer = same meaning, different parts of the world.

Both expressions mean the same - congratulations for doing a good job I hear Australians use 'good on you' a lot. I hear Americans use 'good for you'.

There's no difference in meaning - only of style:) Possibly because I'm British, I never say "good on you" - only "good for you".

I don't think there's any difference.

'Good for you' means it is good for you or you'll get good benefits, example: 'It is good for your health.' 'Her mother is pregnant. Good for her family.' 'Good on you' means that when something is on you, it looks good, example: 'The dress looks good on you.' Both can be use as, like Blake said, congratulations or something like that i'm stil not sure on what other particular events these phrases are used.. but still i'm hoping i've helped :)