I have never used Crank Bros cleats or pedals, so can't offer an opinion.
But I can say that I like to be able to use SPD on days when the road is in good shape, but if I am on my feet a lot because of bad road or loose sand or bad trail conditions or exceptionally steep uphill, I would rather wear hiking shoes that day.
Some time back I wrote up a piece comparing two models of pedals that are SPD on one side, platform on the other. If you go with SPD, this may be of interest to you.
http://www.bikeforums.net/touring/10...l#post18306425
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I would add, that when properly tightened, spd cleats generally stay tight and wont become loose for decades, mine havent anyway.
Of course, there is always the option of taking along a spair set of cleats, but I figure taking care of both cleats and pedals regularly is a big factor in how long they work well (removing pebbles stuck in cleat right away, clearing mud dirt out of pedal mechanism, trying to reduce walking on uneven surfaces and wearing away cleats)
I was touring with someone who had new shoes, and the store hadnt properly tightened the new cleats, resulting in the cleat coming off and staying in the pedal when he took his foot off one time (didnt recognize the "loose" feeling) Luckily we were able to access some tools at a nearby store to remove the cleat, and luckily also the threads were not stripped and the cleat was able to be mounted again.
bottom line, I guess it depends on where you are going and for how long. Not an easy answer from us, but my solid experience with shimano spd will always keep me with them.
I do not fully agree on the bolts staying tight. When you first install cleats on a new shoe, the sole of the shoe is plastic and it will slowly deform from the shape of the cleat. Thus, the bolt will loosen up slowly at first as the sole conforms to the cleat. I think it best to check the bolts after a few weeks, then again after a few months. And maybe the beginning of the next year. I have always found if I do that, I catch cleat bolts that are not yet too loose and I can tighten them up before problems develop. Do not just plan to tighten them once when new. I also carry one spare cleat bolt in my collection of spares, although I have never lost a cleat bolt yet.