Teams & Races
Tier 1
Tier 2
Tier 3
Statistics
Each team has its strengths and weaknesses, and the races are more or less adapted according to the tournament rules (which usually offer bonuses to rosters with a weak third).
Nevertheless, some teams are more frequently present at the top of the ranking, and others at the bottom.
You can check the statistics of NAF tournaments to get an idea: Table of statistics by race (by Sann0638).