Nokia Link (For PC & Mac) lets you sync your photos, music and videos between N9 and computer. It works with iTunes and iPhoto, so you can sync your favourite playlists, videos and photo albums easily.

So, no Contacts, Messages, Maps syncing or even Software/Firmware updating, this is different from NOS


Additional infos (via nokiagadgets) is that you can set your default USB mode from: Settings > Accessories > USB