I love this little gizmo! It's great for fine work not calling for a lot of surface removal or when a belt, or orbital or random orbital sander can be too aggressive.
A tip: the replacement pads available are somewhat limited in their grit range. I have found it useful to save old, worn out pads. Then I buy flat sheets of less common grit (like 400, 500 or even 1000), cut to the same shape as the old pad, use contact adhesive to stick it on the old pad and, presto - a new pad of a grit not normally available!