What functionality of iTunes is not available anywhere else? I commonly use iTunes to add items to iPods and iPhones. However, I'm using Ubuntu more and more and I'm really liking it.

Ubuntu has some apps that replicate iTunes, but some features are either hard-to-find or missing. So my question:

What functionality of iTunes is not available anywhere else?
iTunes match is a huge feature for the iCloud integration features for easy streaming and syncing of playlists and metadata across iOS and Mac/PC. Ping is unique, though few would argue this is highly useful.