Backing up Itunes data: Time Machine or drag-and-copy?

I just moved my Itunes data to a new external storage drive. I want to back it up to a second external storage, but I’m not sure whether I should use Time Machine to do that or just drag-and-drop. I’ve used Time Machine a bit before as backup, but I never really learned how to use it for restoring lost data. It seems a bit complicated. What are the pros and cons of either (or any other) method of backing up data?

Why add a layer of complexity you don’t fully understand when you’ve already got a perfectly adequate backup plan?

Time Machine might be a good option if there were hidden/protected files in your folder, but there aren’t any files in your iTunes folder that won’t copy via drag and drop.

Well, for one thing it took me about 12 hours to move my data. Will it take that long to back it up each time?

12h seems ridiculously long. Are you running on slow USB or over the air or something? Do you have a terabyte of movies?
If you have movies mixed in with your tunes, you can copy everything in your “iTunes Music” folder except the “Movies” folder.

Unless you speed up your network or are willing to accept an incremental backup, you’re going to have to deal a long backup time, regardless of what tools you use to do the backup.

Time Machine is an incremental backup, isn’t it?

Yes.