I personally use both words.
The word "mate" seems to be associated with less than reputable characters these days *cough* chavs *cough* so I use it less often.
In terms of it in use; I would use "mate" to someone who I didn't know very well but want to refer to them or talk directly to them, I use "dude" with closer friends and people who I know are sound geezers.
The word "mate" seems to be associated with less than reputable characters these days *cough* chavs *cough* so I use it less often.
In terms of it in use; I would use "mate" to someone who I didn't know very well but want to refer to them or talk directly to them, I use "dude" with closer friends and people who I know are sound geezers.

