I never feel right keeping the Dark Star. For a non-evil character keeping something solely to harvest human (or mer) souls just seems wrong. But for an enchanter I really miss the oportunity for Grand Souls. Bandits and the like are easily come by and not hard to kill but the only other source outside of solsteim is mammoths and there doesn't seem that many of them, particularly near someplace high enough to snipe them. It makes grand souls very hard to come by and much appreciated when you find a filled gem.