I'm in the process of going through my entire music library and reevaluating songs as I create new smart playlists. Is there any advantage to using Grouping vs Comments in terms of smart playlists and using a non-iOS iPod? For example, one smart playlist I was thinking of making was a general "Workout" playlists with all songs tagged (via comment or grouping) as workouts and then creating smart playlists that draw from this large one in timed amounts (like 20 minutes). This way I would have timed playlists for workout sessions and a one large one to shuffle if I'm going to be doing a lot of outside work or something. That is one example. I just want to know if I should choose one or the other or if they serve different functions. Thanks!