Unless you need to reshape or remove serious imperfections I stay away from any power tools. Dowel/casing wrapped with wet dry sandpaper, for more agressive polishing, or just cotton tip sticks suits me just fine.Have rotozip, will attempt.
It kind of depends on the ramp, but you can do more harm with a rotary action than you will with a back and forward polishing movement. If there are side to side machining markes, a soft rotary pad can tend to simply make them worse... as an example. Examine first to determine how you plan to approach the job at hand and it's not always a "one size fits all" process.
It doesn't take much to alter the geometry with a power tool so I avoid it unless I am intentionally trying to alter/expand it or correct a receiver/ramp transition.