"World of Warcraft" classic games are still very different from WoW Retail. For example, playing a Paladin game in a classic game is very different from playing a game in "World of Warcraft" retail. For example, the retail speed is faster and more refined. The classic games are slower and require more polishing. For example, the gains from retail are less, and the classic games will bring more gains.
No matter which version, World of Warcraft will bring a lot of surprises to players. I recently learned about MMOWTS, a highly credited game store that is selling WOW Classic Gold. If you do not have enough gold coins, you can register as a member of the store now, and you will enjoy great discounts.