Difference between "A" and "AA" shows?

What is the difference between "A" and "AA" shows? Also, isn't it true that there are 3 basic types of shows, "A" shows being the top registered shows (like USEF, and AQHA), "B" rated shows which is a local show with some classes offered for registered/breed associations, and "C" rated shows which are you small local unrated shows with classes that do not offer any registered or rated classes...?

A and AA shows are both governed directly by USEF. (in fact, if you are not a member you actually have to pay a non-member fee) whereas some of the B (local) and C (schooling) level shows are governed by USEF affiliated organizations or just the hosting barn's rules. Technically a show's rating comes from the amount of prize money given and level of classes. So typically an AA show would have a wider selection of classes with more prize money, which generally means that it will be more expensive! But I really don't notice a difference between A and AA shows around here. Actually most of the show "series" will offer anywhere from 2-6 weeks of shows in a row and some of the week are A and some of them are AA. Most people stick around for at least a few weeks. Our local (B) shows are run by a USEF affiliated organization and has no rated show classes (ie: they don't offer Childrens, Juniors, etc) but the rated shows around here offer the nonrated divisions (short/long stirrup, etc) on top of the rated stuff. NONE of the shows around here offer any kind of breed/registered classes. But unless you get into the A/AA scene a lot will depend on your location.

Since there are so few B rated shows where I live C shows are taken a bit more seriously. Because you'll have nice horses who aren't quite A level, horses who at their best do well in C, the greener A level horses, A horses doing a cheaper schooling show, and a lot more. Its a melting pot and absolute chaos...