Hadn't got around to it yet, just watched it.
Looks like the Nexus 5 did out do the iPhone on most of the individual app launches. Video doesn't show multi-tasking though, but he did say he will be doing more tests...
They may be coded differently but at the end of the day, they perform better on iOS.
As a user, I would want a product with the best performance, how it's coded is irrelevant to me.