This movie was decently funny. It had its moments where I was laughing hysterically, but there were also moments I found myself thinking, "That was just stupid."
It's a big spoof of "Walk the Line," the Johnny Cash movie, and the music industry in general. Jack White (of the White Stripes) makes a little appearance as Elvis, which insulted me because he claims to call himself a musician while portraying Elvis when my dog's left hind leg has more musical talent than the White Stripes. (Granted, Shadow's a pretty talented dog...)
The Beatles are also briefly spoofed by Jack Black (McCartney), Paul Rudd (Lenon), Justin Long (Harrison), and Jason Schwartzman (Starr)--probably my favorite part of the movie.
The script was well-written. Presentation was good. My only argument is over whether John C. Reilly is legitimate enough to star by himself (without Will Ferrel). My personal opinion is that this movie would have been MUCH funnier if Ferrel had taken the lead and Reilly had a supporting role somewhere.
Reilly's style of comedy didn't change a bit from "Talladega Nights" and even with a sexy supporting cast (including Jenna Fischer, of "The Office", Jewel Kilchner, Morgan Fairchild), it didn't reach the expectations I had for this movie.
My verdict: this movie gets my hesitant thumb up, but could have been better.
But Jenna Fischer was extremely hot.