I am a platform pedal user too--Wellgo MG-1's for me. I found platform pedaling to be more appropriate for me for a number of reasons. I don't have to adjust cleats on my shoes, walk in stiff soled shoes, I can change foot positions on the pedal, and can use most any shoe. I also wear 43's so a platform pedal works better for me.

Here's an interesting article about arch pedaling:

http://www.rivbike.com/article/clothing/the_shoes_ruse