All the bikes I’ve owned have been fitted with PD-M540 pedals. These are double sided SPD clip in pedals. They are quite minimalist, shed mud well and last well. They aren’t the bottom of the range item but they aren’t the super light bling top of the range either.
However, last year I decided to try something a little different. I got some second hand PD-A520.
These are designed for touring. I assume the idea is that the much larger plate to support the shoe means that they work better with more flexible shoes that can also be worn for walking. This is certainly my experience. The PD-M540 work best with super rigid shoes or boots like Sidi Diablo or Specialized Comp MTB. The PD-A520 are ok with more bendy ones like my much loved Shimano MT-60 Goretex shoes.
The disadvantage of the PD-A520 is that they are single sided. This means they are more difficult to clip into. Especially in the dark when you aren’t quite used to them. After a while though, it becomes second nature to feel the pedal and flip it the right way up. I was hoping that these pedals would be good with non SPD shoes. They are not too bad provided they are the correct way up!
I am doing a short commute to a nearby train station every day and it is more convenient to wear normal shoes without cleats for this. So I got yet another pedal to try out, the PD-T780
These are again single sided. But I am used to the flipping over now. Also they have a handy marking on the non clip in side to make it easy to see which way up they are. They work well with flat shoes or spd shoes. They have the additional benefit of orange reflectors on the pedals. It’s always good to be just a bit more visible during those dark winter commutes