I second svsirius. I've had a 500mm Maxi for 10 seasons with never a failure. It gets greased (and cleaned) annually and shows no sign of wear or failure.
I've had occasion to ask for help from PYI for paint recommendation or to get another zerc plug and always been treated in a 1st class fashion.
I wouldn't challenge for a minute the value of simplicity and in that aspect the fixed prop wins, but in all other regards I would recommend the Max Prop.