Interesting part about this calculator about extra monthly cost of ownership that AN pointed out.
However,
The calculator has the following flaws if used that way:
1. It computes the tax savings on the amount you enter for mortgage and taxes (If you included principal it is not accurate)
2. What about insurance ? Which is another 60-100 per month).
If you adjust for these AN might be only spending 300-400 less by renting. Still a good deal IMO.