For my main road bike I switched to SPD-SL years ago but have a gravel/touring bike that I left SPD pedals on.
Hard to really do head to head comparisons, but when I made the switch I definitely like the feel/connection of the SL cleats better for typical road rides - especially on longer rides. Seemed to make be a bit faster on the routes I do regularly but 30% of placebos work, too!
But, any multi-day touring or bike rides with my wife usually involve much more walking - the SL shoes are hopeless for that, even with cleat covers.
I'm not doing that much multi-day touring anymore - If I had to choose one pedal, I'd probably choose the SPD-SL but if I had limited funds and I had to choose between pedal upgrade and say upgraded tires, the pedal change really wouldn't win out.