I know I posted this already, but I put it in the wrong place and wasn't sure if it would be seen.
This plugin won't email all users when I use the admin>email options> and send an email. I noticed in the settings, it says my server time is the UTC time, not the actual time zone set on the server, so I'm not sure if that has anything to do with it. I also noticed that when I go to change my email settings and hit save, a blank page appears.
Not sure if this is related, but I have the group management plugin installed as well, and it says all my users are set to No Email, even though they are set correctly in their profiles.