I haven't used it. I use evernote as my digital capture tool, but not for list managing. I once tryed to use evernote as list manager, but found it somehow cumbersome. (I used it poorly)
Currently I'm using Omnifocus with Os X and iPhone. My MO is manage with desktop and view with mobile. Theoretically evernote would be excellent for that kind of work, but unfortunately it didn't work for me.
Probably a bit misleading note about Secret weapon. Direct quote from site: "The GTD mantra. Four words: Collect, Process, Execute, Review." I just have to ask what happened to organize?
There are some nice ideas there, like daily actions ("You may ask, What is the !Daily tag for? This is reserved for those items you are working to habituate into your life. It really could be called “Make this a habit!”"), but still after quick exploration about site, I was not impressed. I'm left with a vague sense someone is trying to exploit GTD.
Total GTD newbie, better with the GTD theory than implementation.