From iPod PC Transfer:
iPod PC Transfer supports all modal and all version of iPod, iPhone and iPad
You may want to backup the music of your iPod or iPhone, to use your iPod, iPhone with a new computer, to copy songs to your new iPod, or to use your iPod or iPhone in more than one computers.
Your music library is priceless. With iPod PC Transfer, you can easily transfer music, videos, books, ringtones from any iPod, iPhone to any computer, copy songs, playlists, ratings from iPod to iTunes, iPhone to iTunes library. No matter what happened, you can always restore your music library from your iPod, iPhone or iPad with iPod PC Transfer.
What's new in this version:
Version 8.2 may include unspecified updates, enhancements, or bug fixes.
Very easy to use, transferred 5000 songs from my iPod successfully. Don't be fooled by other bad reviews. I think they are posted by the bad competitors. My friend used this tool back in year 2008 and recommend to me. I also tried some others, but this one is the only one real worked. I suggest download it from their website which provides the more up to date version and without advertisements etc.
So far, none. Except it is actually cost 19 USD if you want to transfer a lot of songs. But if you only have a small collection need to be transferred, you may also live with free version.