Both guides have a different look. Many players choose the Zygor guide because of the way it looks, with it’s modern, clean appearance. Zygor has improved it, so its easier to navigate. Dugi Guides interface blends into the game more, as it looks more like something you would find within World of Warcraft. It has icons down the right hand side for selecting your guides and is really easy to navigate.
Island expeditions - Set sail for the previously unmapped isles of Azeroth. Battle in groups of three as you race against cunning rival intruders—or enemy players—to collect the island's resources. Constantly evolving challenges await as you traverse frozen landscapes near Northrend, open the gates of an abandoned Gilnean castle, navigate a war between elementals and more. Can be done either in PvP or PvE against advanced AIs.
Even if you don’t have flying in WoD be sure to get the WoD handy notes. If you have flying simply fly and pick up all the treasures that you can and do bonus objectives. Not every single piece of treasure will be worth it though as some are hidden in caves or are just hard to get. So if you find yourself spending more than a few minutes finding a treasure, just skip it and move on, there is plenty of treasure to go around.
Special mention is the Darkmoon Faire Top Hat and WHEE! buff. While not always available due to the DMF being inaccessible most of the month, if you happen to be leveling when the DMF is running, it might be worth your time to go and get these. AFAIK they do stack with heirlooms, although I have not personally tested it. Fair warning: These buffs do NOT stack with each other, and the hats disappear after the DMF goes away later in the month(unless you only log in when the faire is running).
Mag'har orc - "For untold generations, the orc clans of Draenor battled one another in endless war. But when Gul'dan offered them the blood of his demonic masters, the disparate tribes of Mag'har—the orcish word for "uncorrupted"—refused the dark bargain and banded together to drive out the Burning Legion. United under the leadership of Grommash Hellscream, the Mag'har pledged to one day repay Azeroth's heroes for aiding their cause. As war against the Alliance intensifies, the Horde must call upon the might of the Mag'har to seize victory."
I do not recommend going for TBC, although I remember Hellfire peninsula to be decent, everything else is rather slow. Instead go for WotLK, Borean Thundra gets you levelled very fast, and then you can head straight for Icecrown at 67, which is also insanely fast, although admittedly has a few elite quests. You can go to Sholazar Basin alternatively. 2 zones should get you 60-80 no problem.