Hitachi A/Cs are good. I am using one for the past 4 years.
Decide the tonnage based on room size, number of occupants, equipments(like projector/TV etc, which generates more heat) to be used in the room. If there is open terrace above the room it will affect considerably, likewise if walls are exposed east or west. In general 1.2T from Hitachi should do good job. When I was in market all shopkeepers suggested me 1.5T as minimum requirement. I was in top floor that time in 11x13 room, with one side of the wall exposed to sun light from east. However I went with 1.2 Ton A/C and it does the job good.