We still have a ways to go in functionality for getting a complete studio with plugins on a mobile device (something like vst plugins working on the mobile platform), but feel that is going to coming in the not too distant future.
When I open up my case to my ipad 2, it is almost like going to a Sam Ash Music or Guitar Center store. Tons of cool things to try and purchasing at the ready, all with reviews available and sale prices going on.
Tactile input available on my instruments is where it's at too. See it, touch it to fiddle with controls. Interact with it.
Great stuff.