Though its price is absurd (should be free, compared to many others...), it's simple to use once you've set things right and integrated with iTunes.
You've got to tinker a bit so set-up libraries if you already have existing ones, but once you're done, it's very pleasant to use and becomes quite invisible.
For those of you reluctant about the price, it looks like you can use it for free provided a nagging window which remains more attractive than launching an app... ;-)