Flat Pedal Shoes - Worth it?

   My current commute is about 12 miles one way, and I prefer to ride on flat pedals for the commute. Yes, I'm familiar with the benefits of riding clipless. I enjoy my speedplay pedals and Northwave shoes on a nice ride, but not for commuting.

   Are specialized flat pedal shoes worth it? There have been a few reviews of DZRs (here, here, and here) and I know of several other companies making flat pedal shoes - Fiveten, Chrome, Giro, Specialized. But, but it isn't clear to me if the shoes are any stiffer than say Vans or Converse. Do I spend the money on another pair of shoes (we all have that N+1 syndrome) or just keep wearing "stiffer" normal shoes.