Have shimano mx-30 flat pedals on my CkCx, just under 4000 km last year.
these pedals are wide and large nicely holding what ever shoe or boot I had on.
installed the shortest pins, don't have any problems with slippage or shin bashing.
the convenience of just hopping on and going with what every is on your feet is
great.
my partner has shimano 324 pedals on her bike, she likes the combination of platform
on one side and clip in on the other. they seem to work well for her.