KelRiever said:
Yssaril Tribes and Mentak seem to be the most powerful.
For third place it's hard to pick, but I am beginning to thing the Nekko Virus might just be up there.
As a note, we tend to play with all expansions and all possible optional rules.
Nekro Virus up there? Sure, they're scary from a combat point of view, but their lackluster homesystem, mediocre trades, lack of voting participation and dependence on aggression to acquire technologies are potentially huge drawbacks. Plus it's easy to inhibit them from claiming certain objectives.
I would probably categorize the Nekro-Virus amongst the very low tier; they're simply too inconsistent performers, too random and too vulnerable to alot of factors such as politics. The Alastor - used defensively, mind you - is probably their greatest strength in my opinion, but they're simply too easy to hamstring when good players face off against them.