I have the SPC. So far they are as quiet and smooth as stock, I liked the ability to adjust both caster and camber without removing the control arm bolts. I also like the sealed ball joint and the bushings.
I don't like the massive boots on the ball joint. I have not had mine in for a professional alignment yet so I can't say if the ball joint boot is an issue, but at the moment I have about 5mm clearance between my ball joint boot and the coil bucket and I ground about 3mm of that off of the coil bucket flange. I think I may have a slight amount of positive camber (tops of wheels too far out), it is about 0.36 degrees more positive than it was before I replaced the factory control arms.
2008 SE 4WD, Crew Cab, Long Bed; Leer 180 Cap, 2" Receiver hitch, Trailer wiring in bumper. Cooper 245/75/16 M&S (Winter). Cooper 265/75R16 ATP (Summer). Full set of Hefty skids, TJM Coilover w/HD spring, SPC upper control arms and 2" rear add a leaf plus 1" block. TJM extended travel rear shocks. Pyle backup camera wired to a Pioneer radio.