A great deal depends on what the standard of comparison is.
If we consider the best year or two of a comic strip or panel’s life, Bloom County can go head-to-head with anyone, although the competition’s pretty intense. In 1981-82, there was a good argument for Bloom County being the best comic strip ever, but it went downhill from there. The best five years of Bloom/Outland/Opus is behind that of a bunch of other strips, and the best 10 years is way back.
Doonesbury can go head-to-head with anyone if we’re looking at the best year, two years, five years of a strip. By the time we get to a decade, Trudeau’s fastball has lost a bit of its zip. He’s still worth reading today, but he ain’t what he used to be. His best years were the early to mid 1970s. Still, he’s had enough intermittent moments of brilliance since his prime that there’s a case for his having the largest quantity of good stuff.
The Far Side, likewise. Best years were early to mid 1980s; by about 1987, he’d lost some of his zip.
Calvin and Hobbes can go head-to-head with anyone for any period up to a decade. And definitely has the best ratio of brilliant stuff to coasting crap, since Watterson did a Sandy Koufax and quit at the top of his game.
I grew up on Peanuts, since I learned to read in 1959. Maybe it’s the early familiarity, but while I enjoyed Peanuts in its prime, I never remember being bowled over by it, the way I was by each of the other strips I’ve just mentioned when they appeared. The WaPo runs “Classic Peanuts” but I stopped reading it because their choice of Schulz’ classics were rarely interesting. I’m gonna go with “good for its time” the way an Apple IIe was good for its time.
Al Capp had already become a reactionary by the time I noticed his politics, but L’il Abner was still funny a lot of the time regardless. “Joany Phony” (his take on Joan Baez) was ruthlessly dishonest, but I still get a kick out of his protest organization, “Students Wildly Indignant About Nearly Everything,” or S.W.I.N.E. And even in the mid to late 1960s, most of his strips weren’t political anyway. Haven’t read any L’il Abner since it was in the papers, though, so it’s tough for me to stack it up against the others.