I used to run SPD's on my mountain bikes but when it was time to choose a pedal for CX racing (not just gravel riding) I figured it was better to have four possible, equal positions for engaging the pedal, rather than two. That way I'd have twice as many chances to get going faster after a transition that I would with the SPD pedal. I also liked the way that you can "roll" into the engagement on Eggbeaters, either forward or reverse, again making the transition much faster.
Since using them for a full season of CX racing, I became a convert and loaded up all my off-road bikes with Eggbeaters. Road bikes are a different story, but off-road is all Crank Bros.