I took a quick look at this, and it doesn't seem robust enough to really be helpful. I have my reasons and my strategy for converting, and they don't fit within the calculator parameters. Also, I put in my income as $75K just to have a number, and it did the calculations as if all of my income would be taxed at 25%. I just don't see this as having any real life application.
"Good judgment comes from experience. Experience comes from bad judgement." - Will Rogers
DW and I - FIREd at 50 (7/06), living off assets