i personally dont run them... but i can tell you that i have heard more good things about them than bad...personally though, if i was replacing a stock upper, after i have already installed a set of tubular non-adjustables, the second time around i would definately use adjustables so i could set pinion angle...
When installed on a 1979-93 Mustang, these control arms with their stiffer bushings help limit axle wind-up and side-to-side motion, but will not damage your Mustang's upper torque boxes as a standard urethane-bushed upper control arm would.
What i'm probably going to do is take my stockers and weld/box them up and put urathane bushings in them. I want adjustables but i wouldn't even know where to begin on the adjustment part.