I don't know what would have prompted anyone to make a film about a Swedish stoner rock band. But based on what I've uncovered I can only say I approve.
From the songs I've sampled, they're similar to Wolfmother or early Queens of the Stone Age but fuzzier than the former and less weird than the latter. Which makes perfect sense considering they started out in the early 2000s, right around the time QOTSA hit the airwaves with "No One Knows."
That being said it's also not surprising Josh Homme is featured in the doc talking about how cool the band is.
For the most part Truckfighters - by the way, is that not one of the most badass band names you've ever heard? - avoids sounding too derivative of either of those bands. They're just a bit more psychedelic, a bit more droning.
One gem I've found is In Search Of (The) which has a typical soft-loud rock dynamic but happens to be anchored by a genuinely playful little hook.
Another is A. Zappruder. Think Wolfmother's "Colossal" but sped up and twice as fuzzy. Well worth a listen and they have more at their MySpace.