[Jayasimhan]

MS Office comparison is weak. You pay for MS Office to own the output. iBooks Author is free. You pay Apple only when you produce something out of it and sell it for profit. It is absurd to expect proprietary software to be free.

Based on the past and recent history [think of all the products that Google shutdown recently], it sounds to me that it is much reliable for users, especially if you are going to put your career into it, that the company developing the software is making money from it.