I guess it depends on styles to some extent....... and I agree with the issue of consistency. I have definitely brewed some A's....... But, I am no different than anyone else in that I have had some D's and F's too. To me, consistency is the holy grail of an "A" brewer - brewing great beer, every time - and "knowing" what your beer is going to turn out like.
If I look at the styles of beer I brew regularly:
English beers - Ordinary Bitters and Milds (scottish 70 too) ..... I would have to say this is my most consistent categories and I think I regularly can brew B's and A's.
Light German Lagers - Mainly B's. Some A's once in a while, Some not so great ones from time to time too though.
Browns, Porters, Stouts - C+/B-/B. Always seem to be good, very rarely anything "great" though. Very rare that they are bad either, however.
APA, IPA, Ambers - I have only been really focusing more attention on these over the last couple years, and, I feel like I am all over the place. I have had some great ones..... but I have had some bad ones, and everything in between. I do feel like I have learned a lot this past year though, and am on the verge of getting more consistent with these beers. Individual beers have been B's and A's, but overall - my lack of consistency I would have to say C.
Belgians, specialty, unusual, unique, fruit, sour....... D/F - These are consistently my worst beers. I am just as likely to dump a keg of one of these as I am to drink one.
My goal is to get my lagers and hoppy american ales as consistently good as my english beers - all of those tend to be the beer I enjoy drinking the most, so I hope to get them nailed down over the next year or so.