Pros: Good sound, small size, light, portable, great battery, extendable memory
Cons: UX could be a tad better. Packaging is a (one time) pain to open
It's a great music player that is portable and has a clip to be used while on-the-run. It works well and is simple to use. It supports MP3 and FLAC, the two main formats I love and allows drag drop of music into it. It also connects as a PnP device as well as in managed mode using WMP giving you options on how you want to manage your music.
Over all, it's a great music player. Best at it's price point (as a small portable music player in the iPod shuffle/nano range as opposed to the full display type players).
It's so good that when I lost my first player (I gave it to a friend who forgot to pick it up after lunch :/), I went out and bought it again. And do note, I can't buy this at a local store (in India). I waited for a friend to fly back from the US with this player for me.
That's how good this is ;)
Note: My review is based on the 8GB player I have which exactly the same except for the size and cost. Don't be put off on the money I paid, I paid $53 for the 8GB with delivery off Amazon.