Microsoft has SkyDrive and for those who already have that set up, it is 25GBs free and has an iPhone/iPad app.
Google Drive doesn't yet have an iOS ap and the free volume is a fraction of the 25GB that Microsoft's SkyDrive offers.
Note: those who have previously set up a SkyDrive with Microsoft should make sure to select to maintain the 25GB allowance ASAP as they have cut the free allowance in general to something under 7GB for those not grandfathered in by taking some action now.
I maintain most of my own files on my own equipment and use remote access off a collection of 1-2TB "fire/water proof" drives, but sometimes I want an alternative and SkyDrive has worked well enough for a lot of that too.
Walter Mossberg of the WSJ has a piece in today's WSJ about Google Drive. The full article can be pulled up in a google news search by cutting and pasting all the words from the following quote and entering into the news search:
For years, some people who wanted to store files on remote servers in the cloud have been emailing the files to their Gmail accounts, or uploading them
Google Drive is not just "Google Docs" given a new name, although Mossberg does call it an evolution of (from) Google Docs. I consider it more an evolution from Gmail, because using Gmail as a virtual drive has been done for longer. Google Drive sort of includes Google Docs.