I've been using synapse in beta for a long time now and haven't had any issues, except for the fact that it keeps undoing my deletion of the keyboard shortcut. Kupfer is an alternative that has been around for a long time, which user's may prefer the look and feel of. It's useful to know about just in case one or the other "dies out".
Ubuntu 14.04 users can run the commands below to install Kupfer.
sudo add-apt-repository ppa:kupfer-team/ppa sudo apt-get update sudo apt-get install kupfer