Pros: Fantastic battery life, Good audio quality, Great battery life, good design
Cons: HDD can be fragile at times
Due to the great battery life and an immensely large capacity, it's the optimal mp3 for those with a large collection.
It's also quite durable, I've had mine for 5 years now, and it still works fantastically and looks great too (practically new apart from a few scratches on the back).

Though I do have a few points to make;
- you can set a custom EQ: you just need to go on iTunes make a custom EQ and save it. When the iPod is synced the custom EQ will be too.
- you can play flac, you just need to convert it to alac (which is also lossless). There are free programs available that do a fantastic job at that.
I had a Sansa clip before, but found the sync-ing and labeling of songs to be impossible using iTunes and other apps were too much a pain to use.