I'm finding the fullscreen backgrounds to be problematic for mobile phones.
2 main issues:
1. once the user scrolls down in android or iphone, the background doesn't scroll with the content, and the site looks weird or unfinished
2. the background images are taking too long to load for mobile users.
So I'm looking into a way to disable the background slideshow for mobile users. I'll post here if I can figure something out!