okay ill keep it brief
To play against:
Altarians, useless in games ive played, always lesser civ or bottom
Humans, pretty good the longer there around the better they get until they get be in top 2 or 3
Drath, pretty poor never worthy of attention
Archean, same as drath
Korath, usually toughest player, research powerful weapons very quickly spread fast
Krynn, nearly always do well, although ive now played two games where they've built no military at all until well into the mid-game and after their worlds start to be invaded (probably not a bug but certainly strange ai behaviour).
I dont generally build any military ships until i get med sized hulls and both times the krynn have had no ships at all at this point.
Drengin, usually do pretty poorly, okay against other civs but usually pound them into dust pretty easily, they often get very small starting empires.
Thalaians, do well when they dont just build embassies which they did yesterday with the latest build.
Torians, usually do well and then fold pretty easily around the mid game but interestingly they seem to have the habit of using of using different types of weaponry on their ships, ie laser, missile and mass driver weapons, in games ive played
Yor, are very often the strongest ai civ, 2nd or third certainly
Well theres my opinion