First, you probably know that Pacificas range from decent beginner guitars to world class custom shop instruments. (though the world equates Pacificas with the 112).
I have once posted an opinion on this question having some hands-on experience with the different model pacificas. The best ones being long discontinued so you'd have to search the used market for those.
Ratae is right: this is no direct comparision so this refers to quality and reliability (not configuration) so here is my take:
012 = squier
112 = mexican Standard (or Classic Player) it starts getting giggable from here.
212 = a cosmetically improved 112
311 = only a guess as I never tried one: Quality like a 112? but with interesting configuration.
612 or 604 = American Standard with improved QC
611: a big hit for Yamaha, great configuration with superb quality. check that one out!
812 (HSS) or 821 (shredder)= American Standard made on a really good day by employees in a really good mood.
904 = I'd call this one custom shop quality. Made in Japan with some U.S. parts (warmoth coumpound radius neck, Sperzel tuners, etc.) . Stratiest of all Pacificas. And, of course, it is discontinued...
Mike Stern sig = in the same ballpark quality wise as the 904 (in spite of high numbering 1511) but as a tele model.
912, 921= Shredder guitar on par with Ibanez Jem but different.
1200 series = custom shop quality. very rare floyd equipped.
1421 = HSH version of the 1412 but with simpler cosmetics and not chambered.
1412 = USA designed by Rich Lasner. Highest ever of all pacificas (if you exclude some crazy one-off custom shop examplars) A neck-through with complicated hollow body construction and highly figured carved maple top that costed so much to build, Yamaha discontinued them after only a couple of years. At $2,200 in 1990, it was one of the most expensive production guitars out there at the time. Not sure what to compare them to. With only 250 or so in existence, finding one for sale is unlikely though it happens once in a blue moon..
I might say that the build quality is consistently appropriate through the range but the hardware and electronics start being better around the 600 series. Some Folks buy a lower end pacifica for the good neck and stability and then "pimp'" them with better pups and electronics to get a very decent guitar for less money.