Given that the core membership of the Defenders consists of Doctor Strange, Namor the Sub-Mariner, the Hulk, and Silver Surfer, it's baffling how they find any time to fight threats from beyond around all the brooding and occasional rampage. It's also worth noting that, as heroes, these four have a rocky pedigree: For those less in the know (Not you, true believer! -ed), of the four, Namor and the Hulk have willfully destroyed huge portions of New York City, while the Silver Surfer very nearly got the whole planet eaten by Galactus. All four have hefty emotional baggage, enormous power, and a mile-wide loner streak, making their team-up make about as much sense as an all-Axl Rose supergroup. On top of that rock-solid foundation, the Defenders have a rotating roster of C-list heroes, with the occasional peripheral X-Man or Avenger thrown in for sizzle. The team has continued to exist in some form or another since the early 70's, sometimes as comic relief, sometimes as superhero deconstruction, but never especially effectively. Also, once an elf with a gun prophesied that they would one day destroy the earth together. I really and truly wish I was making that up.
AKA The Canadian Avengers, AKA Wolverine's lame high school friends, AKA "that team with the gay marriage," Alpha Flight have the ignoble distinction of existing almost entirely in reference to something else: They're a lamer version of the Avengers who fight for the lamer version of America. While they should be lauded for managing to keep their Native American characters alive longer than a couple of issues, a feat the otherwise basically unkillable X-Men failed to accomplish, Alpha Flight hit some pretty big, pretty obvious stumbling blocks, including things like: having Sasquatch on your team, having a demonically possessed immortal acrobatic dwarf on your team, having a guy named Major Mapleleaf who is a regular guy who rides a magic horse named Thunder on your team, and killing off your entire team, except for Sasquatch. Frankly, that the Canadian government would create a superhero team in the first place is baffling, since fighting crime in Canada is about as rewarding an endeavor as going diving in the Great Salt Lake. And sure, it's easy to rag on Canada and their half-assed superhero team, but at the end of the day, we'll still have Captain America, and they'll still have Sasquatch.
Of all the terrible, ultra-violent, pseudo-badass superhero teams populating the world of comic books, Nextwave are by far the funniest. Variously petty, stupid, psychotic, and aggressively pathetic, the members of Nextwave were assembled by the Highest Anti-Terrorism Effort (H.A.T.E.), led by Dirk Anger, who chews on sticks of lizard meat and tries, repeatedly, to kill himself with an enormous, lever-operated revolver, if that gives you a sense of where they're coming from. Nextwave travel the American midwest, on the run from the terrorist-funded H.A.T.E. in a stolen experimental airship, destroying unusual weapons of mass destruction and doing good very badly. They beat up a cop. They kill a gaggle of koalas. They steal stuff. Their leader won't shut up about when she used to be in the Avengers. One of them is a shitty robot. Nextwave member "The Captain" used to go by "Captain ???? ," a name so foul that on being introduced to him, Captain America beat the tar out of him and stuffed him in a dumpster with a bar of soap in his mouth. Over the course of their twelve-issue run, Nextwave accomplished roughly nothing beyond beating up a whole boatload of folks and stealing a man's prized polka-dot dress. Truly, they are an American treasure.