Season 1=greatness
Season 2=where are we going with this?
Season 3=just stop.
Would definitely recommend season 1. The rest was a progressively steeper downward spiral in which the creators try to expand outside their box in order to deliver an increasingly convoluted story that tricks the audience into spending their time trying to figure out where in the timeline they are or what's really going on, rather than enjoying a genuine and well told story. The characters stop evolving after season 1 and just play out their roles with the creators continually trying to convince you to identify with robots while recycling themes and scifi gimmicks with an updated facade.