I very rarely use unsharp mask! Most of the time, I do a selective sharpening! I guess it's all a question of taste and it also depends of ur pics!! Unsharp mask works better than sharpening on some pics and vice versa! I don't think there's a particular rule for this!! I'd say do as u feel (see) is best!! Beside, all the advice about these seems to be different! Randy says that the settings for unsharp mask should be "Threshold at 1 and radius at .4" when I read else where that the radius should never exceed 3. So u see, I don't think anyone can really tell what to do exactly. It's just very flexible I believe! ;)