After rolling out an attack ad last month -- crashing a wedding of Apple (AAPL 1.76%) and Samsung fans -- Microsoft (MSFT -0.25%) is throwing another punch.

The software giant's new television commercial ruthlessly attacks Apple's iPad.

A side-by-side comparison of an iPad with a Windows 8-powered ASUS VivoTab Smart tablet is peppered with a voiceover narrative mimicking Siri, Apple's digital assistant. 

"Sorry, I don't update like that," Siri says, highlighting Apple's lack of automatic app updates -- something that even Senator John McCain called out in questioning Apple CEO Tim Cook earlier this week. 

The ad then goes on to take the iPad to task for its inability to multitask with a split screen while watching a video. Then comes the rub about the iPad being unable to run Microsoft's PowerPoint.

"Should we just play Chopsticks?" Siri concludes with someone clumsily playing a virtual piano on the iPad.

It's always been socially acceptable to roll out attack ads if you're the underdog, and Microsoft certainly qualifies in the tablet space. Apple had no problem kicking Mr. Softy when the world's largest software company was down, rolling out the "I'm a Mac" ads that repeatedly trashed Windows Vista.

The unique thing about Microsoft's strategy is that it isn't gunning for just one particular product. April's ad skewered the iPhone cult, hoping to make a name for its partnership with Nokia (NOK 1.88%) in putting out Lumia smartphones. 

Now Microsoft is taking aim at the iPad. 

The Nokia Lumia ad was more about style than substance. It didn't really sell the Lumia as much as it put down the iSheep and CopyBots carrying around iPhone and Samsung mobile products. There was no breakdown of Lumia-specific features that would woo a potential buyer to Nokia's handset. This time the spot is spelling out specific reasons why a Windows 8 tablet is the better choice. 

The effectiveness of Microsoft's attack ads remain to be seen. Clearly Microsoft sees Apple as vulnerable -- something that investors have realized since the consumer tech giant's stock peaked when the iPhone 5 hit the market. Will the market begin to attach negative feelings to Apple products, or will viewers interpret the ad as more sour grapes on Microsoft's behalf for missing out on the smartphone and tablet revolutions?

Either way, it's good to at least see Microsoft hungry and attacking. Complacency isn't a good look on an underdog.