I think Speedplay are pretty robust. Certainly the cleats last longer than the plastic looks.
Yeah, I'm on about the attached power meter rather than the pedal mechanism.
I've used speedplay for time, originally to see if they'd help a dodgy knee but then just because I found them easier to clip in than one-sided pedal.
As you say, the pedals seem to last an age and the cleat lifetime is reasonable, especially for the newer versions that have the rubber cowl. The only issue I've had is purely my own fault and entirely in character where I failed to re-grease them and ended up seizing the bearing, which then caused the pedal to unscrew during a ride. I managed to get home after 7 mile one-leg drill. Lesson learned.