Pisses me off that the didn't send a notification through their app alerting readers of the change. That's the whole point of having a notification system. Plus it bothers me that I'll have to keep two different comics apps on my iPad as I have quite a few issues that I bought prior to the switchover.
IDW handled this in a pretty poor fashion.
I didn't know about this either until I downloaded the update and had to re-download all my comics. Fortunately it was mostly problem-free, although I did lose one purchase which was kinda annoying.