I haven't watched OC & Stiggs in a while, and discovered it accidentally in the first place. But as a fledging Altmaniac, seeing the hate this one gets everywhere I kind of feel a need to defend it. It's meanly funny at times, and sometimes totally lame. While you can often accuse Altman, even in his better works, of condescension to his subjects and audience, I think OC & Stiggs is more mature than it's credited for.
Whether Altman was going for it or not, the film captures the futile (if sometimes actually righteous) anger of teens, the sad bonds of outsider friendship and pending adulthood, and the hyprocrises and prejudices or the "grown-up" world. The only film I can think of on a similar wavelength is Duck! The Carbine High Massacre (1999), a basically homemade "spoof" of the Columbine Shootings (with Skinemax regular Misty Mundae) which is somehow actually funny and poignant.
OC & Stiggs is no classic, but, accidental though it may be, it has surprising humor and poignance, if you're open-minded and had an odd time of high school. It is still probably only of interest to hardcore Altmaniacs; the viewer who wanders in expecting wild teen dick & titty joke hijinx will be disapoointed.