I have owned many iPods over the years. I was a big fan of the large capacity iPods where I could store all of my music files and still have tons of room left over for more. However, I would periodically have issues with some of the models where the music would skip while I was working out or even just walking. It didn't happen a huge amount, and only did so with certain models, but it did bother me. With the shuffle I never have to worry about that. While the larger iPods use a hard drive (like a computer) that can be prone to skipping and damage, the shuffle uses flash memory that makes skipping a non-issue.
Besides the fact that it does not skip, there are other good points for this mp3 player. It's size makes it great for working out and it also has a clip so you can attach it to your clothing. In addition, it is reasonably priced by iPod standards. This is a bonus for me as I no longer have to worry so much about losing and/or breaking the player since it is not too terribly pricey to replace. The battery life seems quite good, although I really don't know how long it lasts.
Some people don't like the fact that the player does not have a screen to display the songs being played. Personally, this doesn't matter to me. I feel that the screen would be just one more thing prone to break on the player and I know all of the songs that I put on the player so I don't need to read the titles.
While this device hasn't replaced my large capacity mp3 player, it does compliment it. This is the device that I use while exercising and I would definitely recommend it.