Sammy . . . like wow. If I can't claim the new boy owns them [...], you can't deny he defines them." Rolling Stones David Fricke rated the album three-and-a-half out of five stars. He said of "Source of Infection": "While Eddie Van Halen sprays you with a machine-gun succession of speed-metal-guitar arpeggios, Sammy Hagar sends out the party invitations with his usual savoir-faire — "Hey! All right! Whoo!" Alex Van Halen and Michael Anthony, of course, take him at his word, shooting into hyper-beat space before you can say, 'Jump'." He noted that "Van Halen, contrary to purist grumbling, did not wimp out when Diamond Dave hit the bricks. Nor did the band go — ugh! — pop: the 5150 ladies' choice "Why Can't This Be Love" wasn't really a ballad; it was more like Big Rock Melancholia. In fact, all the 5150-model Van Halen did was replace one mighty mouth with another and trot out some hip, new songwriting tricks." Still, he stated that "the curve balls [...] don't always hit the strike zone. "Finish What Ya Started" is an unexpected turn into wheat-field-rock country." Despite this, he concluded that "maybe Eddie and company haven't been pushing the envelope, so to speak, far enough in terms of songwriting. But "Mine All Mine" is a good teaser for the future, the slow stuff is classy radio fare, and at its best, OU812 is a veritable feast of great white rock & roll wow." Xavier Russell of Kerrang! was more enthusiastic and called OU812 "loud, rude, dirty and very much a Van Halen album". A retrospective review from AllMusic's Stephen Thomas Erlewine was fairly positive. Erlewine stated that "when David Lee Roth fronted the band, almost everything that Van Halen did seemed easy – as big, boisterous, and raucous as an actual party – but Van Hagar makes good times seem like tough work here." Still, he stated that "the riffs are complicated, not catchy, the rhythms plod, they don't rock, and Sammy strains to inject some good times by singing too hard." However, he concluded that "if it isn't as good as Fair Warning (even if it's nearly not as much fun), it's nevertheless the best showcase of the instrumental abilities of Van Hagar." Canadian journalist Martin Popoff defined OU812 music as "cynical corporate rock" and found the album "over-produced and actually more commonplace" than its predecessor 5150, implying