AIMS, "Sungoldpower", "Oneinverter", "Ouyad", "Upsen" and "Sigineer" inverters (the low-freq models with 120-204v split-phase outputs) are all extremely similar and appear to be made by the same factory, Yiyen. I suspect Sunray Shenzhen inverters are also made by Yiyen. And probably a few other brandnames I have not seen yet.....Maybe its just a cheap AIMs clone?
The point is that Yiyen's inverters are sold under a TON of assorted brandnames. It's perfectly legal, since these are meant mostly for off-grid or mobile applications. If you want one with UL type approvals you will have to pay loads more for the "premium" types like Schneider or Outback Power. AIMS has some inverter models that are "ETL conforming" and alleged to conform to UL standard 458. They SHOULD be acceptable for home solar installation but I suspect you would need the blessing of a professional electrician.
I have had a 4kW AIMS and a 6kW Sigineer. They are amazingly similar except the Sigineer has a built-in display. Both of them consumed about 50-60 watts at idle with no load, so you may have gotten a bad sample. I put a scope on the outputs and saw very clean sine waves, even under some load. They are not BAD products--you just can't expect the built-in fans to cool them properly. You MUST put plenty of external fans around them if they are exposed to temps of 80 deg F or more. Take better care of them than the "serious industrial" types.
Like a lot of industries, the inverter manufacturing base in China is a crazy mess, with dozens of resellers buying OEM inverters and remarking them--and pretending to be the original manufacturer. Applies to all other solar-power products too. Be aware of this.