I have been using the Voltas Vertis 1.5 Ton Ac for the past 3 years with out a problem. I purchased it for Rs17, 000 and I feel that it is good , evecpt for a certain level of noise that is common in every window AC. But care has to be taken for cleaning the AC over time to time for a proper cooling or else the cooling level drops. Window Ac has its advantages like low maintenance and easy cleaning where as they have a directed cooling and lot of noise which tends to increase over a period of time.
in case of Split AC they are costly difficult to maintain and clean by our self but good spread of cooling the whole room and less noisy. I opted for the window AC for my bedroom cos I had a window made for that
My power bills shoot to an extra 1000 for the summer season for a whole night usage/.