Another newbe

Hi. I'm new to Gregg and am wondering what the major differences are between the versions. I know you guys get this question all the time (having read half a dozen of them already on the discussion board) and I already took a look at the comparison, but I still have questions. What are the major differences between the systems? I guess what I am asking is, If I learned one system, DJS for example, would I be able to read anniversary? Forget the breif forms, how alike are the mechanics? thanks for the help. 

(by -strawman- for everyone)