Capitalist: Capitalist is a very good resource gainer for more expensive and time taking strategies, but it is bad at quick reactions. If you are more of a simpleton (no offence), then you wouldn't have changed your government and it would be on capitalist. Either that or you chose it. Capitalist is very efficient to adapting to your partner's weak point, considering it has no major income apart from money.
Monarchy: Monarchy is a more all rounded government, as it has both units based for defence, and offence. If you like more varied tactics then monarchy is the one to go for. It is also good for helping your partner in hand, as you can create medics from both of it's main unit deployment structures.
Facicist: Facicist is very much based on attack and quick reaction. you can have a unit that counters almost everything from it's forge, and it can have the power to easily own the opponent with a quick romans rush (Do not call it nooby it isn't). However it is very weak to powerful attack and defence, and will mainly only do damage in hordes of expensive units. Even though a single sakata spider can easily destroy a base with no aids.
Communist: Communist, although rather strong in offence, is mainly from what it looks like defence with the exception of black queens and marines. Its tanks can easily defend a rush, and its hover tanks can penetrate any missile barrier from monarchy or facicist. However, almost every powerful unit focuses on more than 1 resource, so you would need a lot more resource buildings.
