In 20 years road riding I’ve used just about every clipless setup you could imagine apart from Keywin. This would be my advice:
Start off with a set of Shimano. They have a solid interface, have some float, and the cleats are by far the most robust of the road systems.
Look are useful if you like Shimano but need a bit more float – 9 degrees with the red cleats. The float is also a little bit easier than Shimano. The cleats are less robust than Shimano, though, they have a tendency to squeak.
Speedplay are very popular with people who have knee problems, and fitters who need to to adjust cleats a lot. They require lots of maintenance. And the cleats cost a lot. The pedal bodies also wear, so TCO is much higher.