Sounds like you got a bad egg. I've been using an Epic that was upgraded to an Epic Dragon in the same body for over 4 years and the thing has been through rain, sand storms, not covered, avalanches, blizzards... you get the point. And yet i've never had an issue. I'm on the original 5" screen, same cards, and batteries and those also have been flawless.
Only issue i've ever had is a fan going down, but that was my own fault.