I have experienced almost every brand in my office and home in the past 10-12 years... Pel, Dawlance, Hier, SG, LG, Waves, Mitsu, General...
Currently I am using an LG, a Waves and a Mr. Slim...
My Conclusion is, if you have a higher budget, buy a Mitsubishi Mr. Slim there is No AC matching to its performance and quality available in the market right now. Same goes for General.
If you have a slightly lower budget Go for LG... Otherwise Go for any brand, all are same, just the outer shell is different... They perform well for 2 years, after that its your luck but in most of the cases they just die on you or need regular maintenance. like Gas filling or thermostat problem etc.