I use the Buddypress Group Email Subscription - linked below.
I have been having a variety of issues with it, specifically with the daily digest. Although the developers are awesome - many know Boone and Dwanaus on this site - I continue to have a lot of issues.
Regardless I am researching whether there are any alternatives to this plugin - specifically one that offers daily digest options. Can anyone point me to another plugin?
And don't let my experience scare you away from their plugin. They update it regularly and I have exchanged emails with them and gotten help, but I am at a point where I am about to start losing subscribers so I need to look at more serious options.