I think Roger Ebert put it best: Kevin Smith's movies are either for you, or they aren't. Here's what he had to say in his review of JSBSB:
"Jay and Silent Bob" will be seen as a self-indulgence by Kevin Smith to those outside the circle of his films--and by those within it as Kevin Smith's indulgence to them.
And don't get me started on whether it's plenary or temporal. This is one of those movies where the inmates take over the asylum, by which I mean that the director was obviously unrestrained by any timid notions of "reaching the biggest possible audience," and allowed to make an in-joke of epic proportions. Like the Monty Python movies, it depends for full enjoyment on your encyclopedia knowledge of the world that generated it."
In short, you have to be Kevin Smith fan to be a Kevin Smith fan.
I'm a Kevin Smith fan. :D
This is my first time reading the whole thread, and I have to say that I'm surprised that everyone has their own idea of what his best film has been (though it seems like everyone disliked "Jersey Girl"). For the record, "Chasing Amy" is by far my favorite Kevin Smith film, while I also thought JSBSB was hilarious. Even "Mallrats" wasn't the turd every critic said it was at the time.
Re Clerks II:
I actually liked this better than the original. True, it isn't as raw as the first one, nor does it have its free-form insouciance, and it certainly isn't as quotable. But I really liked the heart in this one, the revelation of sides of character never even guessed at in the original. And the "porch monkey" and donkey scenes had me in stitches. :D