There is a lot of misinformation on mate and caffeine.
The oldest myth is the mateine myth: "Mate contains no caffeine, it has mateine, a different isomer, instead. The problem here is there is only one isomer of caffine. Long ago there was this same debate with theaine/teaine [not to be confused with theainine an amino acid in tea] versus caffeine.
The next myth is that Mate is high in caffeine. Actually mate is lower in caffeine than coffee and much lower than tea.
Mate is about one percent caffeine by dry weight [source:http://www.erowid.org/plants/yerba_mate/yerba_mate_chemistry2.shtml]
Coffee is between .8 and 2.5 percent caffine [source: http://www.douwe-egberts.co.uk/uk/Retai ... CoffeeFAQ/]
Tea is between 3 and 5 percent caffeine. [http://220.127.116.11/search?q=cache:2zLRC6gLA1AJ:www.toolsofnature.com/gpage140html.html]
So, why does every one say the opposite order? Because of amount used.
People fill gourds 3/4 full with mate. People use one tablespoon of coffee per cup. People use one teaspoon per cup of tea.