The Matrix Online does not have any instances - it is the only MMO truly without them.
Guild Wars is an interesting game, but it IS NOT an MMO. BY definition an MMO would have thousands of players in one world at one time, not 8 people in a Deathmatch map.
Lets call this game what it is - a 3rd Person Unreal 2K4 mod. All they are missing is a player matching server which would make it easier to form groups.
And yes, I've PLAYED it for at least 4-6 hours already.