A great review of Zygors i to 70 Alliance and Horde Leveling guide.
When you read through, it outlines many of the basic advantages of using the guide. For instance it mentions how the guide enables you to find the quests you require and then automatically directs you to the location it can be completed, which mobs to take down and how to mash them. Once the quest is complete it then automatically directs you to the exact place and NPC you need to hand in to.
No more Leaving the game to find such information.
There are so many other reasons to use this guide.
But the real main advantage of using this guide is that every thing is automated. The information pops up exactly when you need it and all waypoints directing you are entered automatically to produce an arrow which steers you towards what ever your objective is.
It means that now your WOW leveling is totally uninterrupted and along with the fact that the guide is highly detailed, this shaves days off your leveling times.