I currently have central air but I have lived places with window installed air conditioners. I prefer the central air because it utilizes energy saving technology that keeps the electric bill low. Now most window installed air conditioners also have energy saving technology but it is way less effective as it only registers the temperature near the unit itself. You can utilize timers with central air also so it requires far less interaction. Also when a window installed unit runs out of freon then in most cases you must toss it and buy another where as with central air it simply requires a refill every few years (about $100-$200 depending on size of home).