For me it was only being introduced to this system since GenCon and not knowing where a lot of the resources were for stats and such. Having started in Advanced DnD, playing Battlemasters as a kid, and some others like Shadowrun, VtM, and Travelor I could get a general idea and do some internet digging.
Ultimately, it is trying to gage the game flow because each has their own vibe. Layout and design were easier because of a bg in Graphic Design, for myself.