When I am compounding, I prefere smaller pads like 6" , when I do light polishing 7,5"-8" and finishing I use 8-9" SM Arnold 80ppi, very soft pads.
My next rotary will be the very light and strong Flex L 3403 VRG, only 4lbs and a couple of oz! For us in Europe itīs 1,9kg. That is very very light, I have never tested a Dewalt but they do look heavy and bulky. The flex have 1300watt so itīs not that powerful like the bigger ones, but not so weak either. A superb machine!
Is Flex represented in North America? Anyway take a look at this link
http://www.flex-tools.de/en/prod/detail.php?id=164
EDIT:
After some reading I now know that the Dewalt 849 is 8,25lbs!

No wonder why you think itīs heavy. It is!.
Itīs almost twice as much as the machine I use today
AEG PE150
http://www.aeg-pt.se/internet/CmsTEST2003A.nsf/Files/PE150Z1.jpg/$FILE/PE150Z1.jpg