I run flat triggers on all my 1911s and 2011s. I like the consistent feel and pull, regardless of where my finger hits the trigger. I also like how they look. But it is purely a matter of personal preference - I don't think there's a substantial enough difference between flat and curved to make a big performnce difference. Trigger length is MUCH more important than the shape of the trigger.
I have run both the Caspian Trik trigger and the SVI trigger with interchangeable trigger faces. Since I prefer a medium flat (roughly equal to a long curved), and the Caspian trigger costs 1/3 the price of the SVI, I have a cost preference for Caspian.