I rode SPD for many years. Then I worked for several bike shops and wanted to be educated on everything, so i tried everything. The exact problem i had with Eggbeaters was clipping in. My cleats would just slide down those two little polished "tracks" like a wet bike tire on a trolly track. My everyday cycling in the city grid required INSTANT clip-in without fail at times. I could never feel confident with the Eggbeaters having missed the clip-in too many times. The SPDs have a little "arrow head" on the cleat that finds it's spot on the pedals and STICKS there while I add weight for the clip. 999/1000 no-fail clip-ins for me.

If I were a serious minimalist / "weight weenie" doing club rides in the country or road races on closed roads where I clip in at the START of the race and don't unclip until crossing the finish line, I could see going with Eggbeaters. For urban traffic riding, not for me.