I prefer to look at each Star Trek as a seperate show. Obviously they arent, they take place in the same galaxy and even share some characters, but each show has such a different tone that I just regard them all as seperate. I guess every new Star Trek is like a new Doctor stepping out of the Tardis. They might be similiar, essentially the same thing, but they all have very seperate personalities. For this reason, continuity errors never really bother me. The Borg in TNG and the Borg in VOY are different. The Klingons in TOS are different from the Klingons in TNG which are different from the Klingons in DS9 which are different from the Klingons in VOY. Some incarnations (the Voyager ones) arent as good as the others, but I dont feel the need to compare them as actual cultures.