From A.O Scott’s review in the NYT:

To say that the movie is not funny is merely to affirm the obvious. The word “unfunny” surely applies to Mr. Myers’s obnoxious attempts to find mirth in physical and cultural differences but does not quite capture the strenuous unpleasantness of his performance. No, “The Love Guru” is downright antifunny, an experience that makes you wonder if you will ever laugh again.

Roger Ebert:

[Meyers] has a strange manner of delivering punchlines directly into the camera and then laughing at them — usually, I must report, alone.

Myers has made some funny movies, but this film could have been written on toilet walls by callow adolescents. Every reference to a human sex organ or process of defecation is not automatically funny simply because it is naughty, but Myers seems to labor under that delusion. He acts as if he’s getting away with something, but in fact all he’s getting away with is selling tickets to a dreary experience.

Stephanie Zacharek in Salon:

The picture, written by Myers and Graham Gordy and directed by Marco Schnabel (no relation to Julian), is listless and pokey, chiefly because watching Myers in this particular guise is almost completely joyless. He does nothing but beam and mug for the camera; his fellow actors barely exist. […] As an Indian stereotype—or even a faux-Indian stereotype [Meyers is] not nearly as funny as the Bollywood-via-Tennessee pharmacist Padma Perkesh, played by Tracey Ullman on her show, “State of the Union.” Ullman’s Perkesh can turn a laundry list of Viagra side effects into a lavish yet compact two-minute musical extravaganza. Myers wastes a good 90 minutes trying to summon a transcendental boner.