It's about balance, Seamus. The corsairs get the best shieldbusters in game, that compensates with less maneuverable ships. The outcasts get a smaller bomber powerplant, and the inferno. Other factions get either unique stuff (e.g. The Barghest and Fafnir have an additional CD slot), or simply a little better handling, but that's all.
You should also know that in this current version, the outcasts are really spoiled with one of (if not) the widest variety of ships and equipment.
