I work from home with an iMac (2014 BTO) in my home office, and previously, a Macbook Pro 15 retina (2015) as my computer when out of the office. However, earlier this year, I retired the Macbook Pro to my wife and tried to move my mobile computing to my iPad Air 2. Mostly, it's been a success, especially with the recent release of iOS9 and multi-tasking.
However, some of my gripes have been the smaller screen, which becomes even smaller with 2 apps, and the need to carry a separate bluetooth keyboard (Logitech Keys to Go). I know there are keyboards that attach to the iPad, but I don't like the way they bulk up the device. I also use a stylus, but the lag along with its lack of fine accuracy can be irritating at times.
So I'm really looking forward to using the iPad Pro with its bigger screen. Using a single app will mean less squinting (I'm getting older now!), and when using 2 apps, they'll still look fine without looking like a squished iPhone version. Also, the Apple Smart Cover with keyboard is something I'm looking forward to using alongside the Apple Pencil.
All in all, the iPad Pro and related peripherals look like they've been released specifically for my work case!