Several users have tried to email me via Special:EmailUser (i.e. via https://en.wikipedia.org/wiki/Special:EmailUser/Sven_Manguard), but I have not received the emails. Other mail sent to the same address through other means is arriving normally. When I attempted to determine whether this was a Special:EmailUser specific problem, as opposed to one with my gmail account, I asked user:Hahc21 to sent me an email through both methods. He also reported having problems receiving mail via Special:EmailUser recently.
I know of at least two users that tried emailing me, Cyberpower678 and Darkwarriorblade. The former sent an email a few days before 8 April 2014 and another one on 8 April 2014. The latter sent me an email today, 14 April 2014. I received none of them. I was, however, able to reach them using Special:EmailUser.
The email address that is hooked up to my account is the same one I am using here, for Bugzilla. I changed the capitalization (SvenManguard@gmail.com to firstname.lastname@example.org), and was then able to get an email via Special:EmailUser from valhallasw. I am not sure if resetting my email address changed anything, but I've yet to test anything further.