I've been very happy with the A530 SPD/Platforms for touring. During my last tour, the only shoes I brought along were Shimano SPD sandals ( http://www.zappos.com/shimano-spd-cycling-sandal-brown ), and they worked fantastic. The sandals were very walkable off of the bike, even more so than the mountain SPD shoes I normally wear. One thing you may want to look out for is that the footbed is pretty long, which is great for protecting your toes, but you may encounter toe-overlap issues with small framed bikes.

Unlike the other posters so far, I would definitely stick with the dual-sided platforms for touring. After being in the saddle for 6-8 hours a day, I found that being able to swap to the platform side and move my feet around completely eliminated any issues I had with being locked-in for that long.