A really different feel from the season 1-3.... but it is a whole different animal really.
They released it all at once because it is pretty much made to watch in a row. It is a very interesting project in that way. Not a traditional TV Series, more like a really long movie. It is designed to be taken in as one piece.
Being so long, it does get a bit jumbled. I can't help but wonder if they could have edited it in someway to make each character's story actually run parallel like in the earlier seasons, rather than revealing new aspects to a scene/event each episode.
I do like the plethora of new characters, and all the various dangling plot threads (provided we get another season that is).
I already said this before, but probably the biggest little thing that bothered me was actually young George and Lucille being played by different actors. Especially Seth Rogan. Took me "out of" all flashbacks, and I nearly missed the point of one when I didn't recognize it was supposed to be Lucille.
Annnnyways.... Probably gonna give it another watch to get everything straight.