I religiously DVR'd every episode until this current season. My system was to watch it a given episode for as long as it held my interest or made me laugh. As time went on, I found that I was shutting off most episodes about ten minutes in. This season, I cancelled the season pass and haven't looked back.
Really, the Simpsons has been, at best, an average sitcom (meaning not very good) since 'Season 11.' Yeah, there might have been a decent episode here or there but you could say the same thing about 90% of the shitcoms that have polluted the airwaves.
The only episodes over the past few years that have been slightly above average in my estimation are some of the Halloween specials, and that's only because they aren't constrained by maintain a status quo.
Ultimately, as good as the first nine seasons were, given the ratio of bad seasons to good at this point, I don't think you can actually call 'the Simpsons' a good show, only a long running one. Trying to define the entire run by the early years is akin to saying that 'Lost in Space' wasn't camp merely because the first few episodes were darker in tone than all the ones that came after.