I think it's been pretty funny these past few years. There's a lot of filler, sure, but I generally dvr the show and skip right through it. I don't like Fred Armisen's Obama at all. I didn't like the guy who did Bush after Will Ferrell left, either.
Anyway,SNL's always had it's ups and downs. I still cringe out how horrendously unwatchable the show became when the line-up that revitalized the show in the late '80s/ early '90s had almost all left the show(Hartman, Farley, Rock, Sandler etc) to become superstars. We were left with David Spade, Tim Meadows and a bunch of new people, and the show became total crap. It picked up again with Norm Macdonald and Will Ferrell, and even Jimmy Fallon, then it got crappy again. I think Andy Samberg and Keenan Thompson have injected a lot of new life into the show, though. Some of Samberg's sketches are among the funniest in the history of the show, IMO. I've seen "Dick in a Box" at least a hundred times now and I can't forsee a time when it will cease to be hilarious. Same with anything featuring Blizzard Man. "Mother's day" was great, too. "Deep House Dish" is a great recurring sketch, and I like "What up with that" as well.