Season 4 is the last season of Breaking Bad I got to watch before going on hiatus to wait for the final part of season 5 to make it to Netflix. It continues to trace its route as a Shakespearean tragedy. Walter's just gonna keep being Walter.
This season continues Breaking Bad's run as one of the best shows on TV. So much has been written about this, I don't have much to add, but it's excellent TV. Watch it.