I found Blue Harvest to be good, but really Family Guy is scraping the bottom of their joke barrel. Blue Harvest poked fun at Star Wars, not near as well as Robot Chicken has, but it still provided decent humor on the subject.
Something Something Something Dark Side (SSSDS) seemed to be just a reason to put FG characters in ESB. It never even attempted to poke fun at star wars, and honestly, the jokes that would have been funny, have been made stale by repetition on the show.
I honestly think the best writing ended when the show was canceled by fox years ago. Reviving a show like that is like bringing a long-dead corpse back to life to win a beauty contest. Somebody might enjoy it, but aside from watching it to avoid paid-programing, the show lost my interest after the 3rd 15 minute chicken fight.
In the end, if you are going to watch one, watch Blue Harvest. SSSDS is something that might make you laugh, but I dunno. Take your chance with it.