My buddy Robert Montgomery and I have been buying comics in DC since 1989 when we started working together and fell back into the hobby hard. Here's his thoughts on Final Crisis (which I have not read):
OK. I bought all 7 issues of Final Crisis and all I get at the end is a big HUH? Typical Morrison surrealism. Judy's right when he says DC should have gotten Geoff Johns to write it. What I think happened is: the Multiverse was re-established thanks to Superman; also, the New Gods are back. Is Darkseid? Dunno. Is the Martian Manhunter? I'd bet he is. Looks like we now will get a series of stories explaining how things have changed. Eh. It looks as if Morrison brought in a bit of stuff from the cross-overs. I know he brought in characters from the Superman cross-over (which must have been terribly confusing to those readers who didn't pick up that story and who were wondering where the vampire came from). All-in-all -- what a mess.