If you are comfortable and experienced in flying 500's I can appreciate why you would want to stick with them, they are second to none for their utility applications.Maintenance is not the issue that they seem to be labled with either. My choice would be to go for a 530 FF,there was a very informative artical in vertical magazine a short time ago,looked ideal for a hook machine. With regard to Kg's on the hook, they rate them in the class of the 407. I have flown a 407 on water bombing ops, with a 50 ft line & bucket, great machine, but I would walk past it for a 530.