I think it's just basically a personal prefence. My whole life I had been doing face first, then eyes, only to have to touch up the makeup around my eyes again because of fall-out. Then I discovered the concept of putting extra powder under the eyes. I've just recently switched to eyes first, then face. I think I like doing it better this way because 1) less concealer/powder/foundation gets used, and 2) my face still looks fresh as I'm walking out the door. Before, I was always having to touch up my face makeup but my eyes looked great! Now, everything looks great when I put on the finishing touches and walk out the door.
But sometimes, I still do my face first then eyes. I guess it just depends on the color of e/s I'm wearing. No matter what though, my mascara and lipstick/gloss always goes last after powder or e/s. lol.