there are 32 reviews on the apple appstore so some people have already used it. apple doesn't show download numbers so it's difficult to know how many actually downloaded it.
Here's my very conservative definition of 'real work': filing your own US tax return.
I would personally find it painful to enter all of that information on a tablet myself so I bought TurboTax Premier for my MacBook Pro (with the 17 inch screen and typically an attached 20 inch monitor).
I also like using a full-size keyboard with Cherry MX switches. You don't have to check what you've just typed.
For real work (answering technical emails, writing code, debugging, writing specs) I want a PC with at least two monitors.