I play the English - ultra symmetrical variation.
I started playing it because:
1) You can do the same first few moves regardless of what your opponent does (within reason, obviously).
2) As implied by the name, the best response for black is to mirror white's moves for the first 6 or 7 moves. Since it's not that popular an opening, if my opponent mirrors me for that long, I immediately have reason to be suspicious...
At this point, I'm actually hoping that this opening gets busted because I've got bored of playing it, but currently if I switch openings as white I basically double my chance of losing.
Iron Man opening