You may not have seen Microsoft's latest advert. That's because even the company behind it realised it was a bit embarrassing, and took it down shortly after releasing it.
It showed a couple of marketing types from Apple trying to big up the new iPhones.
Pretty much every feature of the new devices comes in for a slating: the new colours, the price, the fingerprint scanner… Which is all well and good, if it was funny. And - crucially - if it was on the money.
Unfortunately, Microsoft failed on both counts. It slammed Apple for using flowery descriptions for its new colours ("robin's egg blue", for example). But if you actually look at the Apple website, you'll see no such florid terms.
Compare this with how Google describes the colours of its Glass hi-tech spectacles (shale, tangerine, charcoal, cotton, sky), and Apple comes off better in my book.
The 5c's plastic casing also comes in for criticism. Or rather, how Apple markets it.
"Are we going to tell people it's made of plastic?" the t-shirted man from Apple says in the video. "Nah bro'," is the response.
But as anyone who's actually watched the 5c's promo vid will tell you, Jony Ive describes the 5c as "unapologetically plastic".
If you're going for the jugular, you'd better get your facts straight.
Microsoft realised this, and pulled the ad. It released a statement that reads: "The video was intended to be a light-hearted poke at our friends from Cupertino. But it was off the mark, and we've decided to pull it down."
This slagging match has been going on for some time in the mobile world. Microsoft slammed the iPad mini when it launched its first small Windows 8 tablet, but the slate in question - the Acer Iconia W3 - received pretty dire reviews.
The Redmond company has taken aim at Google in the past too, with its Scroogled campaign.
In a similar vein, Nokia accused anyone using an iPhone of being a zombie.
Funnily enough, the only ad of this type that doesn't make me cringe was actually made by Microsoft. It showed a wedding, with the guests divided over their allegiance of which smartphone they used. And it worked precisely because it showed how ridiculous this kind of feud is.
I'm all for a bit of poking fun, when it hits the target. (Like when The Onion skewers social media professionals, for example.) But slagging off your rivals is a fight no one's going to win, and will only turn off potential customers.