nylon or braided polyester for anchor line

[blue trust]

brian and capns i am refitting a 42 brewer cutter rigged sailboat, and have a manson anchor connected to 400 ft of 3/8 inch chain. my second anchor is a 55 fortress with 100ft 3/8 chain and 300 either nylon or braid. this is my question. what is your recommendation for the anchor line on the fortress i am considering 5/8 inch twisted nylon, 5/8 inch multi braid polyester or 5/8 square braid polyester. interested in your recommendations and comments. thanks tom jones blue trust annapolis md