Your emails won't be wiped unless you created a new (unlinked) account on outlook.com, or if you skipped the first option upon changing to an outlook.com account - when it asks you what you want to do with your old emails. It asks if you want to move them to a new folder or to keep them in your original inbox.
SkyDrive maybe, haven't read up on that, but I'm DropBox guy myself. All I know is that the allowance per file has risen.
I'll have to chase up with guys at work who are on Office 365 rollout projects to see if this interface is from that product. It's brilliant and I can't understate it enough, so much better than OWA.