I emphasize that I am not a professional detailer. In fact, this is only the second time that I have used foam pads on the Makita. First time was to buff the headlight lens on my SUV and I am now in the process of completing the compounding & polishing of my cabin sides that were heavily oxidized. The four inch foam pads can access the sides of the cabin better, in my opinion; much easier than using a wool pad. I find that the foam pads are less likely to catch on portlight hinges, turnbuckles, and chain plates. Furthermore, it is my understanding after reading the manufacturer's literature (Lake Country) that the foam pads are constucted of various compositions for specific abrasive features. Yellow pads are for compounding, Orange pads are for polishing, and white pads are for swirl removal and wax applications. I also like the feature that the pads can be rinsed with water to flush off build up. I am not sure if wool pads are available in the smaller diameters. With my limited experience in using the four inch foam pads, I am very impressed with the results and ease of use. I will use them again, in the future, for the cabin and perhaps my scooped stern. Will definitely use the 9" wool pads, that I have always used, for the topsides. Needless to say, I am very pleased that I can now use the Makita exclusively for the entire boat, without having to buy another smaller polisher.
I know that Mainsail has also used Lake Country foam pads. Hopefully he can comment on the pros & cons of using foam vs wool in polishinig operations. He's got a lot more experience than I have as he was a professional detailer at one time.