So far so good, although it doesn’t seem to really be an energy star AC and I will have to see what the electrical bill will be, since I have just started to use it.
 I do notice a slight smell of refrigerant, maybe because it’s new. My building is older, so It has to be plugged into a special outlet, but still after 20 minutes, plug starts to get warm. I do not blame that on the AC, though. 
It is very simple to use, simple to set up the exhaust hose out the window, even to remove it. I purchased some special aluminum tape to make sure the vent out the window is sufficiently secured without drafts. 
The summer has already started to be hot, so, although, I will not be running it all the time and definitely not during the night, I think it is a good fit for my needs. I even enjoy the little jingle when turning it on or off.  The four star rating is because I do not see anywhere that it is an energy star AC