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.
The leveling guides on my site are essentially speed leveling guides. My leveling guides are the same guides I use myself to speedrun to 60 on new servers to get 60 server first. I list many occasions where I tell the player to "die on purpose" to go faster. I tell the player to skip certain quests, because some quests are just not worth the time/XP. I list tricks and shortcuts to go faster so you can reach level 60 much quicker. I am still constantly going through them over and over again perfecting the guides to make them faster and easier to follow. For the most part, the guide can be followed without the need from other player's help, as the whole guide was made from a solo run anyways. Although I do list quests that can optionally be done if you have a group.
Once you have your potions, proceed to complete all the bonus objectives in your starting zone. This should easily level you to 92, where you can proceed to Gorgrond. Interesting enough, for some reason many Gorgrond quests are worth nearly double the experience of quests in other zones. Maybe this is a bug, maybe intended, I'm not sure. But I actually recommend you do all the quests and bonus objectives in Gorgrond. For your outpost choice, I recommend choosing the Gladiators, since they give access to more treasures than the shredder IMO.
Class abilities were reworked dramatically across the board, with some still needing a serious balance pass. That left many players not only feeling underpowered, but having to learn how to play their characters all over again. Bosses in large-group raid dungeons that were easily killed each week by experienced guilds of players suddenly became challenging again, or worse, completely unkillable, halting forward momentum on old content for a good chunk of the high-end player base.
Stormheim is the zone you want to start it. For some reason Legion treasures are not worth any experience like they are in WoD...except in Stormheim. I haven't been able to find out any reason for this, and it's possible it may get fixed/nerfed at a later date. But for the time being you REALLY want to jump from treasure to treasure to augment your quest experience.
REALMS Aerie Peak Aman'Thul Area 52 Arthas Baelgun Barthilas Blackrock Bleeding Hollow Burning Legion Cenarius Dalaran Darkspear Earthen Ring Emerald Dream Frostmourne Garona Garrosh Hyjal Illidan Kel'Thuzad Kil'jaeden Korgath Lightbringer Mal'Ganis Moon Guard Proudmoore Ravenholdt Sargeras Saurfang Shattered Hand Stormrage Stormreaver Thrall Tichondrius Turalyon Wyrmrest Accord Zul'jin Aegwynn, Bonechewer, Daggerspine, Gurubashi, and Hakkar Agamaggan, Archimonde, Jaedenar, and The Underbog Aggramar and Fizzcrank Akama, Dragonmaw, and Mug'thol Alleria and Khadgar Alexstrasza and Terokkar Altar of Storms, Anetheron, Magtheridon, and Ysondre Alterac Mountains, Balnazzar, Gorgonnash, The Forgotten Coast, and Warsong Andorhal, Scilla, Ursin, and Zuluhed Antonidas and Uldum Anub’arak, Chromaggus, Crushridge, Garithos, Nathrezim, and Smolderthorn Anvilmar and Undermine Arathor and Drenden Argent Dawn and The Scryers Arygos and Llane Auchindoun, Cho'gall, and Laughing Skull Azgalor, Azshara, Destromath, and Thunderlord Azjol-Nerub and Khaz Modan Azuremyst and Staghelm Baelgun and Doomhammer Black Dragonflight, Gul'dan, and Skullcrusher Blackhand and Galakrond Blackwater Raiders and Shadow Council Blackwing Lair, Dethecus, Detheroc, Haomarush, Lethon, and Shadowmoon Bladefist and Kul Tiras Blade's Edge and Thunderhorn Blood Furnace, Mannoroth, and Nazjatar Bloodhoof and Duskwood Bloodscalp, Boulderfist, Dunemaul, Maiev, and Stonemaul Borean Tundra and Shadowsong Bronzebeard and Shandris Burning Blade, Lightning's Blade, and Onyxia Caelestrasz and Nagrand Cairne and Perenolde Cenarion Circle and Sisters of Elune Coilfang, Dark Iron, Dalvengyr, and Demon Soul Dawnbringer and Madoran Darrowmere and Windrunner Dath'Remar and Khaz'goroth Deathwing, Executus, Kalecgos, and Shattered Halls Dentarg and Whisperwind Detheroc and Shadowmoon Draenor and Echo Isles Dragonblight and Fenris Draka and Suramar Drak’Tharon, Firetree, Malorne, Rivendare, Spirestone, and Stormscale Drak'thul and Skywall Dreadmaul and Thaurissan Durotan and Ysera Eitrigg and Shu'halo Eldre’Thalas and Korialstrasz Elune and Gilneas Eonar and Velen Eredar, Gorefiend, Spinebreaker, and Wildhammer Exodar and Medivh Farstriders, Silver Hand, and Thorium Brotherhood Feathermoon and Scarlet Crusade Frostmane, Ner'zhul, and Tortheldrin Frostwolf and Vashj Ghostlands and Kael'thas Gnomeregan and Moonrunner Greymane and Tanaris Grizzly Hills and Lothar Gundrak and Jubei'Thos Hellscream and Zangarmarsh Hydraxis and Terenas Icecrown and Malygos Kargath and Norgannon Kilrogg and Winterhoof Kirin Tor, Sentinels, and Steamwheedle Cartel Lightninghoof, Maelstrom, and The Venture Co Malfurion and Trollbane Misha and Rexxar Mok'Nathal and Silvermoon Muradin and Nordrassil Nazgrel, Nesingwary, and Vek'nilash Quel'dorei and Sen'jin Ravencrest and Uldaman Ravenholdt and Twisting Nether Runetotem and Uther
Some dungeons are also much better than other. Some take a long time to finish and some are quick. Some have few quests and others have many. The ideal dungeons have a lot of quests and are quick to finish. If you are sent to a long dungeon that you have already completed, you can leave but you won’t be able to enter a new dungeon in 30 minutes. Dungeons like the Stockade are super quick, so it will still be good XP if you are sent here more than once.
101+ At this point you'll start taking a penalty on quest/bonus objective experience for every level past 100. Treasures, however, remain worth their full value all the way through level 105, at which point they'll be worth something like 15% less, and then another 15% more when you ding 106. I recommend that you stop questing/gathering entirely, and collect all the treasures you can stomach, only avoiding any annoying to reach ones inside caves or behind elites/rares(where scaling does bizarro things).