Lag aside, playing with friends using the DS' local wireless function offers a mostly fulfilling experience, though you'll still need four copies of the game and four DS systems. As a group, each player will create his own character, and you can then free-play different dungeon locations or choose to accept specific side-quests. It's somewhat different from the solo-campaign, which is the game's main focus, but it's a good time nonetheless. Even with a few irritants, Ring of Fates excels in practically every area where FFCC on the GC did not. It's definitely the action-RPG dungeon crawler to own on the DS.
Bottom Line: With a new story, intriguing characters, and ample gameplay updates, Ring of Fates overwhelmingly captures the good aspects and proves on the bad areas of the GC original in handheld form.
Recommendation: Buy it. Plowing through fantasy dungeons with fisticuffs and wizardry on the DS doesn't get much better than this.