I stopped using it when I realized how impractical it is that messages expire so quickly (after a couple of days). Unfortunately that meant I'd basically have to 'call ahead' via some other medium, to remind my recipient to open their bitmessage client.
The only reasonable use case for Bitmessage is that is it runs as a daemon in the background and you use some other means for receiving messages instead of their GUI, such as using a regular email client.