...leave small orbit marks if you use too large a grit and they are very hard to sand out, or so it seems. That´s the ordinary orbital sander. The random orbit sander will leave fewer marks. However, sometimes it´s easier to use the ordinary orbital sander close to edges, easier IMHO to control against the nearest painted edge you don´t want sanded. BE sure to use the finest grit you can use to minimize those pesky orbital marks. OH, and don´t let that sucker get outta control or you will have stretch orbit marks for whatever distance it slid.