I only own one iBook. It was given away free for a day over a year ago. It has DRM, and therefore I can't read it on either of my dedicated ereaders, which means I haven't read it, and haven't bought any iBooks.
I do occasionally read on my iOS devices, but I like to have some choice.
That said, I doubt I will remember to look into this before they patch it.
Not for a book I'm not all that bothered about anyway.