I switched from Shimano M520 (mtb SPD) to Time ATAC XS (mtb) for road and some trail use. The only reason I did it was for better retention, which turned out to be a positive.
What surprised me is how very similar the usage feel of each pedal is (after all they are double sided and use a similar spring loaded clamping system.) I also tried eggbeaters and found them equally similar. It seems to be the difference in feel between these pedals is no greater than the difference in feel between a new vs. a worn cleat or changes in release tension if available.
Al