Same here. Mallrats was fun but Jason Lee and Ben Affleck seemed to be trying to force that Clerks "magic" either by their own choosing, outside influence, or a little of both. Chasing Amy had its moments but the chick flick vibe that dominates a bit of the latter part drags it down. Dogma is awesome when working the comedy angle but a tad tedious when forcing the philosophy/beliefs angle regardless of how much Kevin Smith and I may agree on many issues. Jay and Silent Bob Strike Back is probably the closest any other KS movie's come to Clerks for me but I think the low-budget charm of Clerks coupled with how shitty the acting of most of Shannon Elizabeth's gang was makes Clerks the hands-down winner.
That's about all I've seen of his films that I can recall.