CNET's Brook Crothers claims that with the launch of iOS 4.2, he is pretty much ready to abandon his MacBook Air in favor of full-time use of his iPad. Even before the upgrade to the mobile OS, Crothers found that he was almost exclusively using the 3G tablet in the airport, hotel and plane for his various tasks.
With the new functionality in 4.2 including multitasking, folders and printing he expects that trend to be amplified. The key to Crothers' argument is what he calls the iPad's "grab-and-go" capability. For content consumption and browsing as well as light editing/document creation, the iPad already wins easily; Crothers believes that future upgrades like twin cameras and perhaps even larger screens will only make the choice easier for him.
Unfortunately, Crothers does not mention whether he is comparing the iPad to an original MacBook Air or the new slimmer models that were recently introduced. For writers who don't need to integrate images or multimedia content into their web work (like Crothers) the iPad is a spot-on solution. For those with longer writing tasks, photo research or video editing, a proper laptop may be a more productive approach. Hopefully we'll continue to have both form factors for some time to come.