Marauders are overpowered and very strong.
Magus are underpopulated and underpowered with several bugged spells.
Warrior Priest tend to be semi-unkillable.
Squig Herder are underpowered.
Shaman are powerful.
Disciple of Kaine are semi-unkillable.

Destruction is grossly overpopulated which gives it a massive advantage, though both factions have their share of mature and immature players, you'll be more likely to find an older group of players on Order. Order is somewhat more mature but has quite a gimp due to it's underpopulation.