I have been using iShell very intensly for the last four weeks. I built a huge project with 360 images many buttons and a kind of state machine controlled by a tabbed data file with 300+ data rows and 15 columns. I started off working myself through all the tutorials.

Pros:
You have a vast library of events, commands and elements. You can nearly do everything what you can imagine. It is quite fast. The learning curve for such a complex environment is OK. I needed about 3-4 days working through all the tutorials and tests of my own to be able to start my own project. The programming environment is stable and quite professional. It is really amazing what you can do!

Cons:
The half an hour tutorial to be up and running is a kind of a joke. The project is allready fully built. The tutorials are not very professional. They have many typos und the things you build look ugly. But it is still the fastest way to learn it.
The support is fast but with zero technical help. I did not get a usable answer to any of my questions. The free documentation is absolut minimal and contains no examples. The runtime module seems to be very buggy at least on OS X. You can only use the letterbox type of window. Fullscreen mode does not work properly (the picture has an offset of about 150 pixels off the screen) nor does Custom mode (all the mouse up events do not work anymore). The wrapper does not work either. I had to switch it off to get rid of having an error message after every click of the mouse. Because of the sparse documentation you have to figure out a lot by yourself. You need a lot of time for very simple things. For instance resizing a window. I still don't now how you do it. You can buy a book/CD but you cannot download it :-(. A big handicap if you have to do a project within a very short time and live abroad.
Because of all this cons iShell is clearly too expensive. For a bigger project you additionally need to buy support which makes it even more expensive.

iShell: You will love it and hate it at the same time!