Do you want to easily transfer files between a mobile device and a computer? I imagine services like Dropbox, Google Drive and Microsoft OneDrive can cover the vast majority of your needs, but there is a critical piece in that equation... and that is you must have internet access. Now, what happens when there is no connection and the content is trapped in the smartphone's internal memory? One option would be to physically connect it to the computer, but there is also DAEMON Sync, which works over WiFi, without going out to the Web.
Sooner or later we all need to make some kind of backup with the information stored on our mobile devices. Perhaps it's just saving our contacts' phone numbers, or transferring the music folder to new hardware. Over the years, the most important mobile platforms improved their native backup tools, but the market is full of external solutions that offer a much more attractive level of flexibility. Personally, there doesn't seem to be anything that gets me off AirDroid. An IP number, a couple of clicks, and everything my smartphone has inside appears in the browser...
A new alternative to AirDroid is called DAEMON Sync, and if for some reason it sounds familiar, it's because its developers are the same ones in charge of the famous DAEMON Tools program for mounting ISO images. Basically, all the user has to do is install the server software (compatible with Windows, Linux and OS X), download the dedicated app (iOS and Android) and start backing up content. Personal files never leave to the Web, but move from one system to another via WiFi.
The setup guide for DAEMON Sync still has several sharp edges (for example, the default username and password are "admin" and "pass", which doesn't appear in the interface), and in the case of Android, its support is limited to Jelly Bean 4.1 as a minimum, but we must be patient. DAEMON Sync is young, and its potential is great. Personally, I'm going to keep managing my files with AirDroid, since its support for older Android versions is broader, however, I won't take DAEMON Sync off the radar.