Pluto is very good at assessing relative army strengths based on units within its vision and will always engage when it judges that its army strength has an advantage, and it uses superior micro and targeting to win battles efficiently. The key weakness of Pluto is that it has no memory of units that are not in its line of sight, so it can be easily exploited with fast skirmishing and harassing units, drops, and spreading out artillery units to deny it from seeing the full army strength all at once.

Its other big weakness is that once you get an army advantage you can force it into a turtling position where it will never try to attack you and you can safely colonize the entire map with expansion bases, giving yourself an insurmountable snowballing resource advantage.