Quoth Irving Patrick Freleigh
1. I already have.
2. I would never do it again. It was disgusting.
3. Any hot food from a vending machine has at least a 99% chance of being disgusting.
4. I just don't see any way a machine can create something appetizing in 3 minutes. I can see this catching on someplace like a university where you can have a lot of drunk people wanting drunk food fast, but I'm going to have to pass on this.
Funnily enough, in my state, there are three major universities: one has on-site accomoation for the country folk, one has no on-or-off site accommodation, while the other has a few off-site places. The that has no accommodation whatsoever has a few campuses dotted around the city and country. One of those campuses has one of those Pizza vending machines. And they are disgusting.