Yes Mitsu will be fine for this size of room 
But if ur going for any other brand than buy 1.5 Ton.
The shopkeeper and a guy i know in samsung company he is a manger there and they are marketing gree he is a big fan of Gree. He says its one of the best A/C around i have been to his house and he got around 8 Gree installed in his house 
The shopkeeper told me that he is selling gree for 2 years not a single complain.
But mitsubhishi is better than Gree way better infact. Reason it uses inverted based tech and it save electercity and cools well.