I haven't been here since I graduated a couple of years ago, but I was around when it opened and ate there almost every week until I left UIUC. Super fast and super cheap is the name of Antonio's game. Not to mention the very interesting pizzas you can try by the slice.
Make no mistake, this place is NOT fancy (e.g. patrons can get water out of a big orange cooler). But it doesn't need to be. Antonio's is great for a quick lunch/dinner and it is really, really great for as post-bar food stop.
The bottom line here is: If you are interested in weird shit on your pizza, if you want a quick meal with zero frills or if you are more than a little tipsy, check this place out.