FORTUNE — You’d think Microsoft (MSFT) would get some credit for running a couple light-hearted TV ads that — unlike those awful 2008 Jerry Seinfeld spots — aren’t cringeworthy.

But in the Windows tablet ads that debuted this week, Microsoft used Siri to badmouth the iPad, and some Apple (AAPL) aficionados were not amused.

AppleInsider’s headline set the tone: Microsoft caught lying about tablet size in comparison to Apple’s iPad.

Among the complaints we’ve seen:

• Microsoft has played tricks with the scale, drawing the 10.1-inch-diagonal screen of the ASUS VivoTab Smart as if it were 36% larger than the iPad’s 9.7-inch screen, when in fact the ASUS screen area is 3.55% smaller (Spotted by Elliot Temple of Curi.us.)
• The error was repeated in Microsoft’s Web ad, which described the ASUS tablet has having a “bigger touchscreen.” That language has since been removed.
• PC World found one of the TV ads “hilarious,” but felt obliged to point that although Siri says she can’t do PowerPoint, she can open PowerPoint presentations and she does do Keynote, which is in many ways superior. Besides, it’s up to Microsoft when the iPad finally gets its Office apps.
• PC World also points out that the money shot — $699 for 64GB iPad vs. $449 for a 64GB VivoTab — doesn’t mention that the 32GB iPad starts at $499. (The VivoTab’s list price is also $499; Microsoft must be getting a $50 discount.)
• And as The Verge notes, the ads “casually ignore any strengths of the iPad,” like better resolution, longer battery life and a lot more apps to choose from.