Just finished the whole thing. Absolutely loved every second of it. I cannot wait for more (which apparently will be coming as the numbers are really high for this).
Some people are calling this a disappointment and I think it is only if you were looking for Jesus to be resurrected or just another season of AD. This couldn't be either of those. The first wasn't possible, and well, the second wasn't either. Seven years have passed and jumping back into the story wouldn't work.
If season 4 was the last we'll ever see of the Bluths, I would be disappointed, and not just because I wouldn't get any more AD. Season 4 is not an ending. Season 4 is a stepping block, a puzzle piece, a needed link for the next phase of AD. And it's as brilliant as the first three seasons.
My only gripe is that I really wish they hadn't done the each-episode-a-different-character format. I think it was done well, and probably as well as it could have been done, but it just wasn't right. In each episode we should have very Bluth, but that wasn't the case. They showed up here and there, and the dynamic was off. But, like I said before, this new season is brilliant, and this new format is no exception. The number of hilarious twists and turns that they got out of this was absurd, but it all worked magnificently.
So yeah, all around pretty great. Especially those GOB episodes. Seriously great stuff there.