Recs.
Updated
SpecsUpdate
Pros
Pro Easy to use
You can use Dropbox via website, by installing a desktop client that creates a folder that you simply drag and drop files into, or with their mobile app. Everything synchronizes across all devices used and cloud storage. And Dropbox offers easy methods of sharing whatever is within it.
Pro Up to 18GB of free storage space
Dropbox personal accounts start out free, with 2GB of space, but users can get extra space by recommending the site to friends, or taking part in events like "Dropquest", where users can win extra space by solving puzzles.
Pro Lots of addons and integrations
There are official and third-party Dropbox add-ons that extend the functionality of the service and add ease of use of existing features.
Additionally, Dropbox can be integrated with existing applications to bring its functionality to other apps.
Cons
Con Nocive development model
Takes a lot of decisions that usually damage community, from deleting features to making impossible to use with other filesystems than ext4 because they decided without a plausible reason (they said it was about xattrs, but all modern linux filesystems supports xattrs, so it's bs.)(they remove this later, but it's too late).
Con Problems when synching between Linux and Windows devices (unconfirmed)
This summer I lost thousands of files due to this problem on older projects which subsequently needed revising and had to be rebuilt as tons of the source was gone.
Con Restricted only to 3 devices for FREE accounts
Recently dropbox decreased the number of linked devices to 3, so you can't have more than 3 linked devices. This is problematic if you use Dropbox to sync between your computers.
Con Can unintentionally delete your files if you reinstall your OS without closing Dropbox
If you reinstall the operation system for your PC and you do not close Dropbox, it will delete all files.