Right now, there are 7 different types of subjects you can have (not counting the special Daimyo vassals): Vassals, Personal Unions, Marches, Protectorates, Colonial Nations, Client States, and Trade Companies.
Normal Vassals give you 10% of their tax (or income?) out of thin air, possibly increased by further modifiers that your vassals have (in 1.8; if this is a bug, it should be modified by your modifiers), they automatically join your wars, occupy a relations slot, and can be annexed after 10 years, giving 75% autonomy in all gained provinces. HRE vassals of the Emperor do not take up relation slots if the 6th reform has been passed.
Personal Unions don't give you any special benefits; they automatically join your wars and take up a relations slot. They can only be annexed after 50 years, and give 75% Autonomy in their provinces when this is done. Also, the Union can break if they hate you or you have negative prestige.
Marches get military bonuses as long as they have less than 60 base tax, and they can't be annexed without breaking the March status, which costs a stab and 200 opinion. They also automatically join your wars and cost a relations slot, even if they're HRE vassals of an Emperor who has passed the 6th reform.
Protectorates can be made of non-Horde nations that are >50% worse than you in tech cost modifiers, and those countries can't be made into normal vassals. They can't be annexed, don't cost a relations slot, give you automatic military access and fleet basing rights, transfers 50% of its trade power, gets a -20% tech cost modifier, can't ally anyone (including the overlord, so it's not called into the overlord's wars), is automatically defended by the overlord, and can declare its own wars.
Colonial Nations form whenever you've cored 5 provinces in a colonial region. They do not cost relations slots, are automatically called to your wars, transfer 50% trade power, and give some percentage of their income as tariffs. The tariff rate can be raised at the risk of them declaring independence. They can declare war on Natives and other colonial nations (without initially calling in the colonial overlord). They get 25% of the normal settler growth when they create colonies.
Client States can be created after taking DIP 22, and can be fed any neighboring provinces; they will gain cores on those provinces iff you initially have cores on them. Otherwise, they act as normal vassals, costing a relations slot and having the ability to turn into a march. However, you can't have more than 10 client states. Islands cannot be added to client states.
Trade companies are not actually independent countries; however, you can add certain African and Asian provinces to trade companies, which gives extra trade power and naval force limits in exchange for tax and manpower in the province. In addition, if your trade company has over 50% of the trade power in a trade company region, you get an additional merchant. They also don't give any unrest penalties based on their religion, whether to intolerance in the province itself or global religious unity.
With 1.8/AoW allowing for transfer of occupations, vassal feeding is much much easier than it has been in a long time. Marches and Protectorates cannot be fed much, but all other vassals are fair game. Client states allow vassals to be created without cores of other nations needing to exist in the provinces, and they can automatically be given non-cored neighboring provinces. In addition, Protectorates, Colonial Nations, and Trade Companies give more trade power and income.
What are some other tips for obtaining and feeding subjects, or using them in any other way? And which types of subjects are best under different circumstances?
Normal Vassals give you 10% of their tax (or income?) out of thin air, possibly increased by further modifiers that your vassals have (in 1.8; if this is a bug, it should be modified by your modifiers), they automatically join your wars, occupy a relations slot, and can be annexed after 10 years, giving 75% autonomy in all gained provinces. HRE vassals of the Emperor do not take up relation slots if the 6th reform has been passed.
Personal Unions don't give you any special benefits; they automatically join your wars and take up a relations slot. They can only be annexed after 50 years, and give 75% Autonomy in their provinces when this is done. Also, the Union can break if they hate you or you have negative prestige.
Marches get military bonuses as long as they have less than 60 base tax, and they can't be annexed without breaking the March status, which costs a stab and 200 opinion. They also automatically join your wars and cost a relations slot, even if they're HRE vassals of an Emperor who has passed the 6th reform.
Protectorates can be made of non-Horde nations that are >50% worse than you in tech cost modifiers, and those countries can't be made into normal vassals. They can't be annexed, don't cost a relations slot, give you automatic military access and fleet basing rights, transfers 50% of its trade power, gets a -20% tech cost modifier, can't ally anyone (including the overlord, so it's not called into the overlord's wars), is automatically defended by the overlord, and can declare its own wars.
Colonial Nations form whenever you've cored 5 provinces in a colonial region. They do not cost relations slots, are automatically called to your wars, transfer 50% trade power, and give some percentage of their income as tariffs. The tariff rate can be raised at the risk of them declaring independence. They can declare war on Natives and other colonial nations (without initially calling in the colonial overlord). They get 25% of the normal settler growth when they create colonies.
Client States can be created after taking DIP 22, and can be fed any neighboring provinces; they will gain cores on those provinces iff you initially have cores on them. Otherwise, they act as normal vassals, costing a relations slot and having the ability to turn into a march. However, you can't have more than 10 client states. Islands cannot be added to client states.
Trade companies are not actually independent countries; however, you can add certain African and Asian provinces to trade companies, which gives extra trade power and naval force limits in exchange for tax and manpower in the province. In addition, if your trade company has over 50% of the trade power in a trade company region, you get an additional merchant. They also don't give any unrest penalties based on their religion, whether to intolerance in the province itself or global religious unity.
With 1.8/AoW allowing for transfer of occupations, vassal feeding is much much easier than it has been in a long time. Marches and Protectorates cannot be fed much, but all other vassals are fair game. Client states allow vassals to be created without cores of other nations needing to exist in the provinces, and they can automatically be given non-cored neighboring provinces. In addition, Protectorates, Colonial Nations, and Trade Companies give more trade power and income.
What are some other tips for obtaining and feeding subjects, or using them in any other way? And which types of subjects are best under different circumstances?