Very very very complex to customize, even if you want change the color background it's very difficult !! (i haven't succeed...)
We can't use it at all it's totally useless, 100 layers by comp, in a comp in a comp in a comp in a comp just for make a left right arrival... ridiculous.
It's not easy like you said also for someone who open AE for the first time. The tutorial is too much fast and short, for someone that work with AE is easy to follow you but it not easy to see how it works, how I can made a video of longer duration? What is the "out" on each elements on the timeline and how I can add it on a new one?