Thanks for the video.It's well done.
I will say that in general grinding is faster than questing but the fastest way is ultimately a combination of smart questing and grinding. Joana and other speed runners have pretty much proven this and I find that I can get much more XP/hour when using an optimized quest line (with grinding to fill in areas where good quests don't exist).
Joana's horde leveling guide is a classic and Jame's alliance guide (30-60) is faster than straight grinding as well.
An additional problem with this approach, though, is that the guides will take you into areas that are very populated and on well populated PVP servers, this can erase any XP/hour. The same thing CAN happen with grinding spots, but this tends to be a bit more flexible than leveling guides. Either way, you're pretty much picking your poison when leveling on a highly populated PVP server if you don't get ahead of the pack.