I've got a set of Ducky side printed PBT on my Filco, they are definitely much nicer then the stock caps but they are quite thin PBT caps. Haven't had any trouble with them but I have ordered myself a set of Thick PBT Black on Black caps (Ivan's GB) to replace them. Banggood also had some well priced PBT caps the other day with free shipping not sure how great they are though.