I remember what else I was going to say. With a disk sander you are pretty much stuck with one grit. To change you have to remove the current disk and fasten on a new disk. Each grit will eat up wood faster than you think for that grit. By the same token, each grit will act like it is a finer grit than it is, leaving a smoother surface. Synopsis: A given grit cuts wood away faster than you think and leaves a smoother edge than you think it will.
Enjoy,
JimB
I have two hand belt sanders that I rarely use now. Getting a smaller hand belt sander was not really much, if any, gain over the larger machine. The smaller unit is a Porter Cable. It is a good machine and I recommend it. However, it is heavy. It is as awkward to use in "unusual" positions as the larger belt sander. Or to put it another way, you sure won't use it overhead, up high or on a vertical surface for any length of time.
I said I would recommend the PC. However, I am sorry I purchased it. I don't think I would miss it if it were gone. At least the last few times I used it, the ROS would have worked just as well.
Back to disc sanders: A method of changing disks rapidly would really be an incentive for me. Someone posted a thread about a 12 inch disk sander. He/she put two grits on the disk at the same time. The "donut" part was coarse. The "hole-in-the-donut" part was fine. When you are aggressive, the higher inches per second travel at the periphery is greatly desired. When you are doing finish work, the slower paper travel speed in towards the center is quite satisfactory---probably even preferable.
Enjoy,
JimB