Nah I've played a fair amount of them at this point (WoW, WAR, Rift, TOR). Rift is nice in that there's always something you can do and, at least for me, I don't find too grindy to open a rift or jump in with others to fight an invasion. The invasions they sure do make it hard for you to ignore a pack of strong mobs waltzing through quest killing fields or attacking hubs. Only really a problem if you end up like WAR (or TOR ) was, with zones devoid of PCs
Haven't done any instances as of yet, I might as I have two friends playing off and on.