I use flats on my full sus and M530 spds on everything else including my daily commuter. I have a pair of new ones sitting waiting for the nice new Cotic X that is due shortly… 🙂
M530’s ftw! The fact it’s nearly as cheap (19.99) to buy a pair from the usual places as if is to buy a pair of new cleats at around £14 (which you get with the pedals anyway) just makes it even less of a question… At that sort of price the lack of serviceability that people will throw at the M530 really doesn’t concern me.
I’m told that road spds will give less chance of your foot hot-spotting on long rides than with mtb spds (the three point mount spreads load better maybe) but mtb spds are definitely winners when it comes to muddy feet and clipping in.
I think it comes down to what you already have and intended use. I’ve never come across said hot spotting but don’t disbelieve it exists – just that I’ve not done long enough rides in spds to find it (used to use platforms and skate shoes for everything…)
If your CX bike is never CX’ing or trail riding and is going to be a commuter then road cleats may suit more if you don’t have mtb clipless stuff already. Cleat systems aren’t compatible so it’s new pedals, shoes and cleats to change.
If you already have a clipless system, maybe fit the pedals and see how you like it before committing to replacing everything!