Doesn't that depend on how often you plan to otherwise replace the device? I'm on a three year cycle, consequently $28/month don't seem like a good deal.
Why is this a good deal? Isn't it about $1000 for this machine (let's say 3 years of use x $336/year). Tablets and netbooks are a lot less than that.
But from a business point of view, looking at an anticipated total cost of ownership, it might be a pretty good deal.