166 for ti zeros, 188 grams for ti blades.
Speedplay pedals are light, but the cleats are not. 264 grams for pedal/cleat.
On paper, the look keo blades should offer more platform, power transfer. They also seem to have smoother bearings. The speedplays offer better cornering clearance, and bash capabilities. You slap a keo blade on a curb, and your $275 pedal is ruined. In most cases, Look will warranty any broken blades, but if you crash, the pedals will break much quicker than the speedplay or any metal pedal. The ti zeros I sell for $175, so I save $100 on going to speedplays. Today, during naptime I'm going to be riding a zero pedal on the left and blade on the right, see if there is a difference in stiffness.
The last thing that I worry for the zeros are the cleats. They are metal, they look ruined after 1 walk into the house. Also, if you end up on a dirt road, with a deadend and have to walk through some dirt/grass/mud, anything but pavement, your stuck cleaning out your cleats for a good time before you are able to clip back in. Stay tuned.