To be honest I'm not sure. A friend of mine was a powerflex agent, and he saw the strongflex and thought they felt harder material than powerflex. on the strong flex site they give some kind of figure for the hardness of the material. Not sure if you'd be able to get the same sort of info out of powerflex themselves and make a comparison that way. They feel good for what they are to me, But I have no direct comparison with powerflex. To be honest, polyurethane is polyurethane surely?? I'm sure there is someone out there who can say otherwise. The main reason I went stronflex was that they offered arb bushes as well and a kit for the car came out the same as suspension bushes only from powerflex price wise. Hope this helps.
dav
What is your feedback right now, that you have the strong-flex bushes for some time in your car ? Would you still prefer them to Powerflex, regardless of cost ? My main issue is longevity, as I do not intend to buy bushes (nor replacement arms) again in my life !