And then JP threw a monkey wrench into it by releasing this:
JP - Revolution Trigger
I run a flat CMC and I like the small kick out at the bottom as it serves as a reference point which aids in putting my finger in the same place every time. That said, it makes little difference in the grand scheme of things as I shoot a curved trigger just fine. Triggers are largely personal preference, I've never felt a Geissele trigger that I felt was worth the money.