The polypropylene version (cant remember the brand name) was used when White Heather was re-rigged - it drove me demented! very stretchy, couldnt keep the lug peaked up but the worst thing was the way you simply cant stop it from twisting, causing huge amounts of friction in the forelug and mizzen lug halyards. I tried towing the stuff to take the viceousness out of it but to no avail. I am sure that 3 strand polyester would not have been so orrible.
As someone else has suggested I would buy polyester and get it dirty, better, cheaper and longer lasting.