I'm posting to this forum because my bike is a cyclocross. I use it for fitness, fair-weather commuting, and fun, not for racing. I ride 75% paved roads, 20% dirt roads, and 5% groomed trail. Minor potholes at worst.
I currently have clips and straps. I've chosen the Shimano M-424 as my clipless pedal.
I chose the 424 over the 520 since the 424 has a surrounding cage. I won't be riding not clipped in, but do want to ease my learning process. When I miss clipping in on the second pedal, I'll have the surrounding cage to maintain my footing and try again. And when it's time to unclip (in non-emergency situations), I've got somewhere to rest my foot as I slow down and stop.
I chose the 424 over the 545 or 647 since the 424's cage, though the weakest available, is not going to be hit by more than pebbles on my rides. I'm not concerned with it breaking.
Will the surrounding cage be as useful as I think? Should I go with a more expensive pedal to get a stronger cage, or perhaps choose the pedal with no cage at all?
Clipless isn't hard to learn. If you're using MTB pedals and shoes, the shoes will have some tread on them and with pedals like SPDs there's a bit of a platform there anyway, albeit small. You can still pedal when not clipped in just make sure your clipped before you try to pull hard. Same with clipping out you'll still have room to rest your foot.
I personally H8 SPD pedals, but lets start with the good:
Adjustable engage/release tension. You can make it super easy to get in and out for when you're learning.
Adjustable release tension, on cheaper models it loosens up and you have to adjust it occasionally.
No Float or very little atleast. This means you have to have your cleat set-up perfect or it could potentionaly hurt your knees. Also this means its a little harder to get in.
some people like SPD others don't. I don't like them for cross because they don't feel secure enough when there at a lower tension setting and I find the lack of float freaking annoying.
For cross I personally prefer crank bros because they're the easiest to get in and out of pedal I've ever used, while still feeling secure when you're in them. Getting in and out of them is no effort at all.
It's really about preference though. Time ATAC are nice and easy as well.