I used to use Time, then CB (because I never found time that reliable ironically) then after CB redefined unreliable I went to shimano.
Pro’s :
The cleats seemingly last forever, I’ve worn out shoes with only one set of cleats! My guess is they’re stel where everyone else uses brass?
The float is very positive, you move your foot side to side and at the limit there’s a bit of resistance and a click and the clat comes off the pedal. Time and CB both felt like you hit the springs much sooner, but then actually releasing is a bit vague after that. I can’t say that I missed the alleged float and after a few hours much preferred shimano. The amount of float is still enough that I angle all my cleats in so that they release sooner when twisting an ankle out.
M540 pedals will survive the nuclear winter along with cockroaches and Nokia 3310.
The springs won’t wear grooves into your boots as the cleat itself takes your weight.
Cons:
Mud has rarely been an issue, just look how many cross racers use shimano pedals. But ice is. Riding in snow can cause problems if you clip in and out and walk a lot.
Not better just different.
Shimano pedals get more float and harder to release as they wear. Whereas Time wear out to the point you spontaneously part company with the bike mid pedal stroke. But the shimano cleats probably outlast them by years.