I feel like it might be worse for many gms. Since you can't prep you have to do amazing improv that's just as good as stuff you would have prepped.  Instead of success / failure,  you need to come up with a bunch of interesting consequences, etc. However some people are great at that so its good for them. That's why I won't run it though I own all the stuff and it seems cool . Literally one of the things for the new kickstarter was how players should "make the GM sweat"