The average rating is about a 5. Thanks to some tips from awesome friends, a large number of places I've tried have gotten above-average scores.
DISCLAIMER: Don't be fooled. I can grade pretty harsh. Don't come after me with hate mail because I had negative comments on your favorite restaurant. It's just my personal preference, and is by no means the gold standard.
The lower the rating, the more unlikely that I would return to eat there again (given I have a craving for that particular cuisine, food, etc.). On the other hand, there is no question I would return to a place with a rating of about 7 or higher. To the servers, owners, and managers of any food business given a score of 9 or better, you should expect to see me often, schedule permitting.
If I give a 9+ rating to a business that is not in Oregon (where I currently reside), you can count on me coming back whenever I'm in your neck of the woods.
"Elite (9+ rating)" labels are only given ONCE to a food establishment -- and I will affix it to the most recent update, if applicable.
Because I always try to nitpick, I have not given a perfect 10 rating yet. I always feel a perfect score should equate to a flawless food establishment. I still have not found that place.
UPDATE (10/10/11): I still base my initial ratings off my first 1-2 experiences. But after much thought, I have decided that the only way any food establishment will get a 10 rating from me is to wow me initially (start out with a rating of about 9 or higher) and absolutely blow me away with amazing food, over-the-top service, etc., over a lengthy period of time. It's the only way for me to separate the great from the legendary.
I do increase ratings if I get constant great food and service with each passing visit. But beware, I have also decreasedratings if I get poor service or food the next time I go back!
I've listed 12 factors below that I use for my ratings. Yes, the #1 factor will always be fresh, quality food. While they are otherwise not in order of importance, the other 11 factors may trump each other at any time, depending on the situation.
This is a guide, NOT a strict checklist.
(1) Did I receive fresh, quality food?
(2) Will I try something new from the menu?
(3) Any unreasonable wait times?
(4) Was the staff friendly?
(5) Inviting decor/ambience?
(6) Bargain? (big portions, cheap price?)
(7) What are their business hours?
(8) Are there healthy menu options?
(9) Did spicy food really bring the heat?*
(10) Good reputation?
(11) Limited market > National chain**
(12) Overall experience
* Yes, I love spice. And I love if they bring major heat to the table. But can the place balance immense heat with amazing flavor? That's the million-dollar question.
** National chains may get a lower rating here than businesses with a limited market. I really value having to travel to a certain location to get great food. Commercial chains (i.e., Pizza Hut, Taco Bell, Subway, etc.) are everywhere, so where's the fun in that?