I agree with the last post on the grinding nature of the game. However, partying systems are undoubtfully fairly decent.
But enough on the basic features of MMORPGs. I would like to talk more about the partying system. Parties operate almost as if you're playing WoW, where tanks ideally holds the aggro, and the party is supported by a priest and possibly by a bard (supporting class here is essential). Well, this also seems like a basic feature of the game too, but it is part of what makes the game fun (you don't need to let yourself grind the whole way, you can take a break and party in instances!!). A good run is definitely not easy to achieve, especially on longer runs (even for very strong players). Proper teamwork really matters in this game.
As for individual players (not a group of real-life friends playing together), this game does not forget them at all! This game features party searching system that groups you up with other parties to join instances! Even if you are a group of two, the party searching system groups the two of you up with other parties! This is a really good feature to have AS LONG AS there is enough players playing this game (so far, there seems to be enough).