Upon the death of my older Mac Pro, I purchased the MBPr as a temporary desktop replacement with the idea that I would ultimately replace it with one of the new Mac Pros. However, I am completely blown away by the performance of the MBPr.
Me too. Have owned mine about 10 days, it's an awesome and fast machine. I have it hooked up to an NEC PA271W, no issues. I was going to get the new MacPro but decided it was too new a technology to jump onto first units out. The Retina will keep me happy for quite awhile.