I've used Crank Bros. Eggbeater pedals, strap-n-clip/cage, as well as Power Grips.

I had strap-n-clip a long time ago. You need the right shoe; too tall or rigid and you have issues. Flip the pedal over and you are almost guaranteed to drag plastic and metal on the pavement. With the option of the Power Grip, I'm not sure I would ever use a clip again.

I've used the Power Grips while adventure racing where you are on/off the bike a lot, running through the woods. They work well with about any shoe and could be transferred to a better set of platforms (the pedals that come in their pedal/strap kit is pretty low end). It is also easy to flip the pedal over and use the other side of the platform (not sure if the strap would drag on the pavement being mounted on a touring bike). Very little to break or go wrong. This would be my 2nd choice.

I currently use stiff mtb shoes with the Eggbeaters on all of my bikes (road and mtn) since the cleat fits up between the shoe treads so it is relatively easy to walk around once you are off the bike. I would probably do the same on an extended tour. If I planned to spend a lot of time off the bike walking and hiking and I could only have 1 pair of shoes, I might get a more flexible mtn shoe and use the Crank Bros. Mallet pedals (clipless with large platform) for walking comfort yet have a lot of support.