What type of AC provides better service?
All types of air conditioner is good and should be bought depends on the room condition and budget.
Split air conditioner has two parts - outdoor unit and indoor unit. Split air conditioner is energy efficient and has a soundless operation. Split AC has a rich temperature control than other air conditioner.
Window air conditioner is used for small home or office. The window AC compressor and the evaporator are in one unit.
Portable AC do not require any installation and can be carried from one room to another.
What power AC to buy?
1 ton AC is enough for a room size up to 100 square feet. 1.5 ton AC can cool your house enough up to 150 square feet. 2 ton AC can do up to 200 square feet. Although more space can be cooled by the air conditioner, this assumption will keep the AC well by reducing the load on the AC compressor.