I've been on speedplays for years. If you get the cleat dirty walking in loose dirt or mud they get a bit finicky. I've found a spray with a water bottle solves it.

Speedplay reccomends regular lubing, but I never bother. In my experience, if they're set up right, the cleats aren't a problem.

If you have a 4 bolt shoe, and don't need the adapter, they are lighter, and the stackheight is virtually non existent.

The speedplay website has a nice comparison tool to compare pedals, that you might find helpful.

And they're great for crits. The outside of my shoe will rub the ground before the pedal does.