The review is not accurate, 4 different types of currency is misleading, there are 3 basic currencies, Gold, Astral Diamond and Zen. Gold is used for daily needs (heal pots and dungeon kits), astral diamonds are used for the AH and Zen is used for high end convenience and decorative items. Only Gold and Astral Diamonds can be earned free in game, Zen must be bought, much like TP but can be purchase through the ZEN Broker with Astral Diamonds earned in game, so there is no need to ever drop a single dime on the game.
DDO is a better game all around if you are a team/guild player but the solo/once in a blue moon partier. Then NWO would probably be a better choice because all players in NWO are self sufficient since healing pots are staggered by level, drop for free or cost very little relative to what you earn, and way out class the healing spells. The low level pot heals for 1000 HP while the spell equivalent might hit for 100 if your cleric is lucky and fully geared to amp it.