I have Speedplay Light Actions on my tri bike and recently on a bike trip decided to use Speedplay Frogs on the road bike, which I'll be putting on my road bike for commuting and whatnot (I previously had SPD-SLs and then someone borrowed my bike and put platforms on).

The Frogs have super easy entry (on either side of the pedal), though as a customer of SPD-SL and then the Light Actions I missed the familiar "click" to confirm I was actually properly connected with the cleat/pedal. Getting out of them was even easier than any pedal I've used (other than platforms). The float is not as great as the Light Actions (which are free float) in the inward direction, but that's not normally a problem. Honestly, my biggest problem was getting into them, but that was a familiarity thing - they hadn't yet become second nature. The pedal/cleat is where I expected it to be, it's just a different motion. The cleats are effectively hidden in my Keen SPD-compatible cycling shoes, you can barely hear them hit the ground. I won't be racing in my Frogs, but I really think they are a good all around pedal.

The Light Actions are also dual sided entry and easy to get into and out of with the familiar "snap" of cleat to pedal. The pedal is small and the cleat is large, but it's a big rectangle and I don't find it as obtrusive or as hard to walk in as the SPD-SL style cleat. I really like them. Something about the shape/angle of my hips to knees to feet made them agree with my body MUCH MORE than using SPD-SLs.

My dad has SPDs on his road bike and he seems fine with it. I don't really see that there's a HUGE advantage between 2-hole shoe compatible (SPD, Frogs, etc) pedals/cleats and the full-on road/race-style pedals/cleats, but there probably is some marginal gain. The biggest jump is between platform to cleats at all. That said, I would put Speedplays on my next bike in a heartbeat.