Don't get me wrong, I absolutely love mechanical keyboards. I own several of them (2 Filcos, blackwidow, 2 cherry g80 boards, IBM model m, and a rapidfire on the way) but I believe they do nothing when it comes to gaming. They just improve the feel drastically. And I mean by an extreme. A mechanical keyboard isn't going to boost your KDR up nor allow you to switch weapons quicker nor build probes faster and etc.. I, however, do believe that they may assist with faster typing speeds or WPM (words per minute).
I'm sorry, I just thought I should share my feelings and also, I just recently defeated a friend in a 1v1 dota2 game and he stated it was due to the fact that I was playing on a mech board and he wasn't.... lol.