Heirlooms are special pieces of armor that level up with your character, so they have stats that are always respectable for your character’s level (up to level 110). Heirlooms that fit the head, shoulder, chest, legs, and back armor slot offer an experience bonus. The total bonus is 45 percent if you have them all. It’s also possible to acquire a ring that adds another 5 percent, but you must win a fishing contest acquire it, and that can take some time.
-Bugs- There aren't too many glaring bugs anymore, but you will certainly encounter some. The pathetic thing is that many of the bugs you'll encounter were reported repeatedly during Alpha/Beta and still weren't fixed. Some bugs were discovered after release and players were able to abuse game mechanics without repercussion unless they were one of the more serious offenders. This gave some players a significant advantage over others because they used exploits and at the start of an expansion, that is the time when it's most impactful.
First of all, the value of transmog is decided by rarity and how they look. Some items like Minenarbeithut der Tiefen or Pendel der Verdammnis (they can drop in Uldaman) are worth millions of gold. They are worth so much, because they have a really small chance to drop. Other items are bought well because they look good. Best example in this case is the Glorious set, its legplates Glorreichen Beinplatte reach a 100.000 Gold value easily.
Once you reach 575 you can purchase vendor recipes for the last 25 points. The Blacksmithing recipes are on a vendor in Vale of Eternal Blossoms. You can enter Vale of Eternal Blossoms after completing the questA Celestial Experience (requires level 87). After you completed the quest, you can find Jorunga Stonehoof (Horde) in Shrine of Two Moons and Cullen Hammerbrow (Alliance) in Shrine of Seven Stars.