Although Darth Hater's reporters say that most of the functions are quite impressive, they seemed most astounded by the versatility and awareness of the artificial intelligence of mobs. Sado, a reporter for Darth Hater, comments about the aggro system in the article, "[NPCs] watched you, but as long as you passed by and did not get too close to them or their buddies there was no issue. On the other hand, the roaming Separatist sentry droids would aggro from quite the distance and give chase." Presumably, if you do actually cross the attack threshold, there are a variety of reactions depending on the type of mob. Sado continues a bit later in the article, "The [NPC] Separatist's actions varied once engaged in battle. It seemed as if it often depended on what cover was around them at the time to get behind. If there was no cover and I was near them, one of them would often run away to go get more of their friends." In contrast he says the creature mobs have a larger attack radius and do not take cover.
Much more was discussed in the full article which is available on DarthHater.com, but where do you stand? Does the relative power of the artificial intelligence system influence your choice in MMOs?