do you ride your ss as a road or city bike? i used looks for awhile (very similar mechanism to the ultegra above), and i will say that it works AMAZINGLY on longer distances, but horrible for frequent unclipping. Trying to flip a look pedal with the slick carbon underside of a road shoe is a horrible pain in the ass, especially in traffic. the eggbeaters are multi directional, so this doesn't come into factor. On the other hand, they're a much smaller pedal, so unless they're a platform (like the mallot) you're transferring all of your power into a much smaller contact point (expect hot spots and flex).
those who use the dura-ace/ultegra/105 style spd-sl or look&keo style do so because they 1) climb lots or 2) mash lots or 3) stay in the cockpit for the majority of the ride over long distances.
if you sprint, time trial, climb or ride 75 miles a week or more i'd go with them.

but yeah, i'll let you know how they feel.