I have both the Porter Cable VS and a DeWalt single speed ROS. The Porter Cable, in my opinion, stands head and shoulders above the DeWalt ( I own many DeWalt tools, and love all of them, except the ROS). There is a "orbital speed control" disk on the DeWalt that is just a rubber disk, and I burned through them about once a month. Had to go to a tool repair shop to get replacements, at about eight bucks a pop. The Porter Cable feels much better in the hand, less vibration, and the pad has held up better than the DeWalt. It also accepts either five or eight hole 5" discs, so I didn't have to get rid of my supply of eight hole sandpaper. IMHO, whatever you do, get the variable speed model of whatever manufacturer you ultimately choose. It should only be a difference of 15 ~ 20 bucks, and it is really a nice feature.
In my case, this is the single most used power tool in kayak construction, get the best you can afford, and spend time with it. I made up a T-shirt that says "They can have my ROS when they pry it from my (remaining) cold dead fingers".
Cheers,
Bob