I have been using their 600WATT PSW Power Inverter PWRI60012S since 2009 without any issues...
Has been my so called work horse Power Inverter always ON and is used in my OFF-ROAD POPUP camper setup to power up many of my low power 120VAC required items like Battery Chargers for cellphone, tablets, and computers. Also used for my WX Radio and many of my 120VAC Ham radio support items...
I ran a 120VAC long multiple head drop cord from the Power Inverter that is mounted close to the Battery Bank with one cord going to the Home Entertainment items and the other power cord going back to the Bed area nite stand.
I know this is apple and oranges compared to the 4000WATT setup you are referring to. This would require many batteries to operate it off-road... More than my 255AH setup haha...
No complaints from this end with the AIMS product... Planning on ordering a new one from AMAZON for my Battery Bank upgrade I am currently working on...
Roy Ken