I have Simplex Prestige on a '72 Raleigh SuperCourse. It has been a good set of deraileurs, very low mileage for many years, and ridden conservatively. I sometimes swap out rear wheels and this RD limits freewheel size more than my other bikes. I suppose this is more of an observation than a complaint. That said, I have had a replacement set of Suntour ARs on standby.