I used 'jj' for a while but the short delay to display j threw me off. I have Ctrl on Caps Lock so pressing Ctrl-[ is decent but still: I never got used to it.
I met Bram at Vimfest in Berlin recently and asked him if he remaps Esc. He said something along the lines of: "No, I aim for the upper left of my keyboard and hope for the best".
I too stopped using 'jj' because of the short delay. FWIW I've found ';l' to work well as a replacement. (For a trial period I had them both mapped to <esc> in my vimrc file.) ';l' seems a natural, but distinctive, rolling motion for me and I've never had it conflict with real-world text entry.
