they are essentially, the same machine, nut for nut, bolt for bolt. The 7336 sp also comes with an addition backing plate and a sanding disc. Both come with counterweights. I have purchased both. an 7424 from autogeek and one from lowes when they discontinued carrying the 7336 sp.
dewalt also makes a slightly more powerful r/o polisher, mainly designed as a sander, but i have seen it used at local detailing shops aorund the bay area. like the new UDM, it features a more powerful 4+ amp motor, for more correcting ability than the PC. I have not used either however, for I rely on a rotary for serious paint correction, and the PC for finish work and mild defect correction. I have no complaints about the PC, either model.
hope i was of some help.
