There are some other fine contenders, but I can't argue with the conclusion of the writer here. JLU was and remains the best supers show on TV.
In addition to all the fine reasons the writer mentions, I'll add a couple of my own.
Though the show gave us a lot of done-in-one episodes, vs multi-parters, it often did so in the context of a broader seasonal plot — e.g., the Cadmus / government conspiracy against seemingly uncontrollable super-folk, or Luthor's obsession with getting back long obsession, first with Superman, later with Braniac.
Indeed, being unafraid to to dive back to episodes previous in the season, or even from earlier seasons — heck, from earlier DCAU shows (Hawkgirl's betrayal of Earth in the "Starcrossed" finale of Justice League; Superman's brainwashing by Darkseid, back in his own animated series) meant that everything had texture and nuance and growth to it that belied it being just a bunch of half-hour colorful slugfests.
That applied to the bad guys, too. Luthor is a great example of a character driven in a number of directions, but I'll also call out the pseudo-villain (say, "antagonist") Amanda Waller, here in her still classic body shape that made her nickname "The Wall" physical as well as tempermental. Waller is misguided — sort of — in her planning against a bunch of neo-gods in orbit with a giant space laser pointed downward — but she does it with dedication, sneakiness, ruthlessness, and even personal valor.
We even got consistent personalities and differentiators amongst the "mooks" of the villain world, as different characters — Deadshot, Grodd, Solomon Grundy, Morgana, Copperhead — show up time and again, not as faceless people to be punched out, but individuals who have personal agendas, as much as the flock of heroes in the JLU do.
Good, good stuff — and something we rewatch enough, even though we have the DVD set, I'm angling for the Blu-Ray at Christmas, just to make it that much easier to do so.
Why Justice League Unlimited Was, and Still Is, the Best Superhero TV Show
We live in a golden age of superhero television. Hits like The Flash, Agent Carter, Arrow, and Agents of SHIELD dominate our TV screens. We champion them for their ability to bring some of the most mind-melting comic book sagas to TV—but one show did it all before them, nearly a decade ago: Justice League Unlimited.
Young justice was AWESOME. We will never get to see how good it was going to get!
Lest you people forget Teen Titans.
Oh, I have no problems with (and great love of) both Teen Titans and Young Justice.
YJ was well done (and beautiful), but suffered from a post-S.1 5-years-later reboot, and then cancellation. I would have loved another season (or three).
TT got its time, and was fun, imaginative, and, when suitable, deeply dramatic. I was glad, as time went on, that they pulled in additional classic TT characters, but the scale still felt oddly restrained by the initial restrictions placed on the setting (by creative design or IP restriction): no grown-up heroes (e.g., no Batman to go with Robin). Still, some triffic stuff in that show, no question (tarnished, sadly, by the laff-riot resurrection in recent years that focused just on the goofy elements).
I still maintain JLU (esp as an extension of BTAS, STAS, and JL) was the best, but I have no hesitation rewatching either YJ or (classic) TT.
Hey, I just finished watching "Avengers 2: the age of Ultron". Really good.
+Madeleine Baier I enjoyed A2 a lot, but it was perforce restricted by the bounds of the overall MCU and the time frame in which to tell it. Even factoring in the scope of spectacle, a TV series is always going to have an inherent advantage over a movie based just on the amount of time they can dedicate to the stories.
Or, put another way, even with the overhead of episodic TV, JLU had 19.5 hours (make it 12 hours minus commercials) to tell its tale. No single movie can compete with that.
It's indeed one of the best, though it did have a few weak episodes here and there, and there were some characters who didn't get enough screen time (the Flash barely got any love in JLU until the later episodes, for example).
I myself prefer Spider-Man: the animated series (The CD Barnes one), Batman Beyond, and X-Men: Evolution (to a certain extent on the last one).
+Steven Grant Flash got some great moments in the earlier JL, and some of the JLU bits for him (the mind switch with Luthor, the final battle with Luthor at the end of S.2, his death being the whole genesis of the Justice Lords) were excellent.
Oh, and the Flash Museum episode was awesome.
Batman Beyond is good stuff, as was X-Men: Evolution. I can't speak to any of the Spider-toons, as I've tended to steer clear of them.