I've been running the M520's for a couple of years now and like them, but they are not that great for going any distance in regular shoes. I just got a new primary bike and put the 520's on it and bought some M524's for the older bike that are nice. Decent platform with the dual side clip fairly level with the edges so you get an even distribution on the pedal but still easy enough to clip in an out when wearing the cleats. The dual side is nice since you don't have to fiddle about when you clip in.

I'd only recommend the 520's for a bike that you would be riding more than 95% of the time with cleats, otherwise the 524's are a great versatile pedal for both cleats and regular shoes.

At REI i've seen the 520's for around $50, and the 524's I recently bought were $70. Shoes, you will be probably be starting at around $75 - $80.

I don't work for either Shimano or REI.