Pros/Cons of Air Powered Sanders
I have two of them. Both are random orbital air sanders (ROS). They were both purchased from Craft Supplies, I can't recall the name of the first one that I have, but the second one is Grex, and I prefer that one, as the pistol grip handle is rubberized and more comfortable to hold.
The pros are: when properly used, they can give you a surface that is superior to hand sanding and power sanding with a corded drill or angle drill. You can also complete your sanding is less time.
The cons are: you need a pretty large air compressor to run them. If the tank isn't large enough, the sander will stall out as soon as you touch the piece you're trying to sand. I have a Husquvarna. 60 gallon tank. Because it requires a lot of air, they are noisy, and there's always the odor from the machine (which is NOT and oil free compressor). Combine the running compressor with your dust collector and overhead air filter, and the shop is pretty noisy. It would be best if the compressor and dust collector were in another room/building, but right now that's not possible. So, I always wear ear protection.
I also found that there is a learning curve to using them properly. You are not so much 'sanding the surface' as you are 'finessing the surface' with just the outside edge of the sandpaper. If you press too hard, you'll dig the sandpaper into the piece, either stalling the sander, or worse, putting more scratches in your work. I also found that air powered sanders work best with the higher grits. So I use a corded drill, or hand sand with the grain, up to 180 or 220 grit. Then I use the ROS beginning with 220 or 240 up to 600 grit.
I hope this helps.