I use my iPad 3 all the time. It gets fairly heavy use. Mostly because when I do media consumption, I grab for that device first. Since Photon (Web browser) came out on the iPad, hardly anything out there is beyond my reach on the thing.
Of course, the other aspect is the great music software on it, and I've created a number of things off of it. The most notable thing is Auria, which is a fully-working capacity Digital Audio Workstation for doing large track studio recordings. Sure, I have logic and everything, but I love how exportable a lot of iPad stuff is so it really can be a usable portable studio for you to create stuff out in the middle of nowhere without the need for power sources before you may decide to bring it back home to finish it off (if need be). Only the iPad could I trust to take with me, go without a power-adaptor. Finish a whole session, balance, tweaks, review, and not even be around an external source of power until I get home. Outlet dependency be darned. Of course, it's still not as fully loaded as a computer with Logic Pro or Protools. It's missing a lot in terms of midi, samples, and such, as that one is made specifically for live recording, at this time. But it does indeed work with plug-ins like the big boys do. Still, I'll whip out the Garageband for some quick work when midi-based songwriting comes into play. The iPad Audio-Clipboard allows me to share recordings and data across different Audio Workstations and virtual instruments.
I also use it for Documents and such, on the go. Even spreadsheets on the go. Those docs are shared to my home computers.
I like to consider it, the convenient workhorse that is usable in a lot more environments. However, it isn't a main workhorse. For obviously big projects I use the computer. But for starting big projects without the convenience of being somewhere that I can use the computers, or for smaller ones, the iPad gets used.
I normally use the iPad to use and answer on this forum. It's just that this time, I'm at the computer. Both, of course, allowing me to use voice dictation to enter this stuff.