I currently use a 500-sheet box of Polymax FB paper that was bought fresh about 2005 and stored in cool, dry conditions. It works as new. The image is quite cold in Dektol with the slight greenish cast that is only evident when viewed alongside an otherwise identical print that was given a short dip (3-4 minutes) in selenium toner.
Like all cold tone papers it doesn’t change color much in a direct toner (except to loose the slight greenish cast in selenium). But it tones nicely in bleach-redevelopment sepia. That can be subsequently toned in gold toner to produce reddish tones.
In Dektol it develops in the usual 2-3 minutes depending on the exposure. Polymax is capable of producing high contrast if wanted.