Short tech takes
The SanDisk Ultra +Cloud is a USB 3.0 flash drive with a twist: You get 64GB on the drive itself and 64GB of cloud storage.
The Ultra is a mid-sized USB 3.0 thumb drives that comes loaded with 64GB of standard onboard storage -- but also contains apps for Windows and Mac systems. When you install one of the apps, you are asked to provide a user name and a password. From then on, when you run the app, it gives you access to your 64GB of cloud storage, which appears as a separate folder in your Finder (if you're using a Mac) or your File Explorer (if you're using a PC).
You also have access to your cloud storage (which SanDisk licensed from Bitcasa) via the Web, so you can find your files even if you're not using the flash drive.
The 64GB of cloud storage is free for three years. If you decide you want more storage space, you can obtain it for what, in today's market, is a reasonable price: $3.99/mo. for 250GB, $6.99/mo. for 500GB and $9.99/mo. for 1TB. This is approximately equivalent to what you would pay for, say, space on Google Drive, which currently offers 15GB free (almost 50GB less than you get from SanDisk, but without the time limit), $1.99/mo. for 100GB and the same $9.99 for 1TB.
For additional security, the Ultra has a copy of SecureAccess so that you can encrypt the data on the flash drive.
Certainly, SanDisk (which is in the process of being bought by Western Digital) has provided an interesting approach to mobile data storage. Users who rely on the more well-known public clouds like Dropbox, Google Drive or Microsoft's OneDrive may shrug at something like this, but if you have some carry-around data you can't trust to the cloud -- and some that you can -- the SanDisk Ultra +Cloud could be useful.