The actual machine is identical as far as I'm aware. 7424 is marketed as a polisher and the 7336 is marketed as a sander - so the only real difference is the attachments that come with them, which you probably wouldn't ever use. I do believe the 7424 has the 5" counterweight and the 7336 has the 6" counterweight (please correct me if I'm wrong).
Go for whichever machine you can get the best deal on.
yes the 7336 and the 7424 are the same except the counterweights are different. and i think the 7336 is/was more popular as you can buy it from Lowe's for about a $100, although you do have to buy the backing plate and pads separately and from another source.
Awesome, thanks guys. I'll probably just go with the 7336 because I can get it from Lowe's, then order the backing plate and pads. Will the 6" counterweight work for polishing and all that?
I have the 7336 which I purchased from detailers parardise, It came with the 6" counterweight, the stock PC pad, sanding disc and sanding disc backing pad.
www.properautocare.com has some information that could prove to be useful. Select Problem Solving in the left column, pick one of the topics, and select its section dedicated to Orbital (dual-action) polishers.