The ease of use, design options (customized layouts). I have been able create 3 different versions within 2 months for my clients without any assistance from our graphic designer or production team - this was fantastic! And it's quick too with no fussing around at all really once done :) No issues yet that we can think off but they are there if needed so far everything has gone as smooth sailing which i am very happy about. Would highly recommend using gingersceney because what else do u want after your book goes into print?