Documentaries about musicians gravitate towards dysfunction, because that’s how you get drama into documentaries and most musicians — especially in bands, where too much time spent together yields unnatural tensions — seem to be pretty dramatic anyway. So it’s curious that both Anvil!: The Story Of Anvil and Iron Maiden: Flight 666 played at SXSW, because they’re about as diametrically opposed as movies about metal bands that’ve lasted over 30 years could be. They’re both love letters, but one has to convince the audience to care; the other is pre-sold.

As for which is better, that’d be Anvil. This is made out of love as much as any sense of “what a story”; the last shot (a post-credits photo of director Sacha Gervasi as 1985’s best-coiffed teen metalhead with his then-favorite band) confirms that it’s a gift from a former teen fan, when music matters most. In the early ’80s Anvil was on track to join Metallica and Anthrax in the upper echelons of commercial success; their hit “Metal on Metal” led to them playing alongside Bon Jovi in 1984 in Japan. But something stopped them, and though Slash, Lemmy, Scott Ian and Lars Ulrich all turn up at the start to testify to Anvil’s lasting importance to metal, none of them have any clue what happened to them or why.

Much of Anvil plays like a companion piece to The Wrestler, with very anachronistic looking dudes trying to do the same thing they loved 30 years ago, when the commercial moment was still there, and still get the same recognition. Instead of one Mickey Rourke, there’s two: Steve “Lips” Kudlow and Robb Reiner. They were nice Toronto boys, both Jewish (Reiner the son of a Holocaust survivor no less) from different worlds: Reiner’s dad encouraged his musical ambitions, Kudlow’s didn’t. But they got together and started rocking out; 35 or so years later, they’re still the best of friends. They’re the only core members left; new members come and go, many of them thrilled to be playing with their childhood idols. Anvil want to bring the rock globally, but it’s hard when Kudlow drives a van for a catering firm and Reiner’s a sandblaster. They have a small, devoted Canadian cult and the inevitable fan strongholds in Japan and Scandinavia, but their worldwide presence is otherwise non-existent. They want to be worldwide touring stars; instead, they’re superstars for a small group of people and schmucks everywhere else. Gervasi follows a European tour (full of elated crowds in the strongholds, disastrous elsewhere), Anvil’s recording sessions with metal legend Chris Tsangarides (their producer for a brief shining moment in the ’80s) and their general failure to return back to the life they had briefly and want again.

There’s a few things to point out right from the top: this is not a movie about the business of being a musician. If you go around the internet, you’ll find vague allusions to “bad business decisions” that stopped Anvil dead in the ’80s; no one in the movie specifies what those might’ve been. Anvil claimed they were badly handled by rapacious indie labels that never paid them, and so now they feel like they have to get signed to a major or stick to self-distribution; clearly no one’s told them about what’s happened in the record business in the last, oh, 15 years or so, or how tiny the chances are of a proudly out-of-step metal band making a major dent in the shrinking market. Speaking of which: Gervasi may love this band, but he’s smart enough to know most people won’t. “Metal on Metal” is a ridiculously catchy song (all together now: “METAL ON METAL/IT’S WHAT I CRAVE/THE LOUDER THE BETTER”), but these are uncompromising metal jams, and I’d imagine that about as many viewers will care for them as care about, say, Yngwie Malmsteen. Hardly any are heard in their entirety; this is about the personalities. Audiences may root for Anvil to regain their touring status, but they probably won’t want to personally be there.

From its premiere at last year’s Sundance, Anvil has been extensively hailed as a real-life Spinal Tap, but it’s sadder than that. Kudlow and Reiner are both family men in every sense, and Kudlow at one point borrows some £13,000 from his sister so that Anvil can record an album “properly” with Tsangarides. The fact that Kudlow announces “Family is important shit, man!’ is apparently an endless source of one-liner hilarity to some people, presumably because the juxtaposition of rote sentiment and blurted profanity is incongruous, but I’m personally kind of touched by Kudlow’s unvarying vernacular; it just makes everything more deeply felt. Anvil is occasionally funny, but it’s mostly sad; it’s also a little slick, but it’s not dishonest. Kudlow and Reiner fight, but at the end of the day they’re family and stand-up guys, trapped by ambitions they don’t really understand how to realize. Someone should give them a crash course in how the industry works now.

As for Iron Maiden: Flight 666: it’s not very surprising it won the Audience Award for best film in the 24 Beats Per Second music category. The world premiere screening had regular attendees way outnumbered by very dedicated dudes (and they were nearly all dudes) in their best Iron Maiden t-shirts — though no one could top the two dudes sitting in the front row, who rocked out like Wayne and Garth to every number, until one of them took off his shirt and twirled it. These guys should be at every screening. The movie itself is 113 minutes long, and probably about 70 of that is concert footage; Maiden fans will get their fix, though I remain unconverted. Iron Maiden is fun for a while: they’re game performers who put on a good show, I have some sympathy for bombastic metal, and I was amused that they even played their infamous musical version of “The Rime of the Ancient Mariner.” Still, 70 minutes of Iron Maiden all blurs together and will wear you down.

But what’s fascinating about Flight 666 is how utterly conflict free it is. It’s kind of a cliche that metal bands generally consist of smiley, genial, well-adjusted guys, but Iron Maiden are also clearly a major business: the big hook is that they built a custom plane to tour, and it’s no gimmick. The back half of the plane is for gear, the front for a crew that totals 70 people (!), and having their own plane allows them to do things that would normally be logistically impossible, like tour Australia with ease. In other words, Iron Maiden is a very well-run corporation in everything but name, and watching them genially negotiate their tour with no problems or personality conflicts whatsoever is pretty refreshing. (It was especially apposite since two days later, Metallica hit the music fest, and journalists interviewing them spent more time staring in wonder at Metallica’s huge organization of handlers than actually getting anything worthwhile from the interviews.) Mildly funny and very sympathetic, Flight 666 is, as weird as this sounds, soothingly boring: it’s nice to see a band get along so well and make their money without any fuss.