However, Mac users will be pleased that resource forks are now handled correctly, making full syncing possible. Macs handle files differently from most other operating systems, saving a small portion of file metadata in a hidden file and the bulk of the data in a larger visible file. Because of issues syncing with other operating systems, most other sync and backup programs simply ignore the resource fork, which can cause problems for users of applications such as Quicken and Quark Xpress.

Windows, Mac, and Linux clients all receive the Selective Sync treatment. Because of cell phone limitations such as patchy connectivity, and Google Android already work on the basis of selective synchronization, whereby users individually choose which files to download from the Dropbox folder.

Dropbox faces competition from an assortment of other providers, not least of which is Microsoft's . Although not supported on as many platforms as Dropbox (only Mac and Windows clients are available), Live Mesh offers 5GB of free storage compared to Dropbox's 2GB. However, .

Dropbox's strength as a cloud offering is that data is mirrored on the users' hard disks alongside the cloud. This eradicates the traditional concern of adopting cloud services, which is one of reliability. If Google Docs becomes inaccessible, for any reason, then any user relying on it will be unable to work.

However, with a file stored in a Dropbox folder, a local copy of the file will always be present, and the file will be synced again as soon as possible once the service returns to normal, should an outage occur.