I was just curious how many of you use Diamond Sporting Dog Formula, and how it compares to ProPlan? I've been using it for a little while now and it seems okay, but I just here so much about ProPlan. I was just curious what you guys thought. I know that the price difference is pretty significant, $16 50lb Diamond/$20 something for a 20lb ProPlan. I might be off a little on the ProPlan figure but I know it's a little bit more.