Their product is okay, but even if it were amazing it wouldn't have been worth all of the headache I've endured with their billing department.
I've had considerable trouble with ISSUU's billing department. I had set my account to be closed last year and had received email confirmation of this fact. However, they continued to bill my credit card ever since. Even after writing them again and agin, they would not refund the money. So, I was forced to go to my bank and contest their charges. So very frustrating.