I was one of the few kids I knew growing up in the 90s who didn't have cable television. My TV viewing was limited to Saturday morning cartoons and the TGIF lineup, except for occasional Nick viewings at my friends' or grandparents' houses. Thus, I did not get to see "Pete and Pete" until the recent DVD releases. So far I have watched all of season 1 and an episode or two from season 2 (thanks to bootleg DVDs).
It's an excellent show that basically epitomizes what it's like to grow up. The International Adult Conspiracy is a hilarious idea, and didn't something like that cross all our minds when the adults in our lives were ganging up on us? The storylines are both funny and poignant, the soundtrack is awesome (Polaris!), and the show is made real with constant references to things like the awful song "Marmalade Cream."
On the commentary track for "Day of the Dot," the show's creators/producers discuss how various aspects of the show (both brothers named Pete, Mom and Dad's first names, Mom's plate) are made mysterious because mystery is a part of childhood, and kids these days maybe know too much. I think that sums up "Pete and Pete" pretty perfectly: a piece of nostalgia for everyone, regardless of whether the viewer watched the show as a kid.