Any thoughts as to which is better? I hear Speedplay offers more float while DuraAce is more restrictive. Please give me your thoughts as I am buying a new bike and want to upgrade. Thanks
There are two schools of thought one of which you will have to decide is your view. 
1)Float is good and allows your feet/knees to move naturally as you pedal.
2)Float is bad because it allows your feet/knees to move naturally as you pedal.
I’d read up on it and it’s going to come down to what YOU like best. I like no float and it works for me. I use Keywinn pedals myself and love them.
I switched from speedplay to DA due to the larger platform of the pedal. I reallly don’t think it made a difference though. I really didn’t notice the decrease in float either, down to 6* now with the shimano pedal. I will tell you that the ultegra and 105 pedal work as well as the Dura Ace pedal and will save you some money. I have all three and really cannot tell a difference while riding.
Speedplay Zeros are great, with incremental adjustments for in and out float, and the smaller contact area is likely no factor if you have carbon-soled shoes—it may be a factor if you have more flexible soles where you can feel the pedal. I switched from Look to Speedplay about a year ago and am perfectly happy. I think you’ll find many people on both sides of the fence.
DuraAce is good enough for Lance.
Why settle for less than the Time Titan Mag? Do it right (even if they are French)
I have both DA and Ultegra pedals - they are pretty nice. Better than my Looks, never tried Speedplay.
Speedplay Zeros are great, with incremental adjustments for in and out float, and the smaller contact area is likely no factor if you have carbon-soled shoes—it may be a factor if you have more flexible soles where you can feel the pedal. I switched from Look to Speedplay about a year ago and am perfectly happy. I think you’ll find many people on both sides of the fence.
DuraAce is good enough for Lance.
I also went from Look to Speedplay (about 10 years ago). I agree with a carbon soled shoe you won’t feel the smaller contact area. The speedplays are just a breeze to get in & out of.
I don;t think it is a matter of which is better. I sell and have used both. I have my preference but no one pedal system is best for everything/everyone.
I may use titanium Zeros at the Nice Triathlon to save weight on my bike. Otherwise I use Dura-Ace SPD/SL.
I have the ultegra’s and they have plenty of float, a nice wide platform and you can walk in the cleats really easily.