i've been using t he apc upe es 500 for many months with minimum problems...it had a minor electircal problem...some loose conection...the apc service centre located near my place fixed it within half an hour...did a through test...free of cost(it's under warrenty) overall i'm very much satisfied with it..i would highly recommend it to one and all..since it has good service network through out india...and it is an excellant product.... u should not have any major problems with it...if u run across it within the warrentry period then then service centre located in your city will replce it if they cannot fix it