I love my finis Neptune, its the formula 1 of waterproof MP3 players. I have to admit it is pricey but you do get what you pay for in this instance. I have tried other less expensive devices over the years but generally find the leads got tangled and the inear 'headphones' fail. I was forever stopping to adjust the inear headphones as water got into the ear rendering them useless. The controls were a nightmare to use and quite frankly I didn't use them whilst swimming.
I have no such trouble with the finis Neptune, there's no ear pieces to fail, the leads are short so they dont get tangled, the controls easy to use even when attached to the back of the goggles. No more stopping to let the water out of the ear pieces leaving me to complete my swim without the constant stop start of previous players. The sound is great and is louder/clearer once you are in the water, the sensation is different which takes some getting used too but that only took a few lengths. Overall the best device by far, and with the 4gb memory a good size too. Wish I had tried this in the first instance rather than going for the less expensive options. Definitely recommended