I stay with standard rubber bushings. One of my wrenching buddies had Polyurethane bushings installed in his Alpina and threw them out again and replaced by OE rubber. They made squeaking noise when not well lubricated, in your link they also mention: Lubricant Included, so that means they need lube every few years. Higher road noise, increased vibrations, increased harshness. There are also positive points for Poly of course.
But no need to type write it down, read here ... Rubber vs Polyurethane Suspension Bushings http://www.suspension.com/blog/rubbe...sion-bushings/
Armstrong seems to be a distributor, not a maker. Never heard of them before.