Voicemail offers the following key features:
Voice Mail Menu
Review Voice Messages (while reviewing messages)
Play Messages (after reviewing messages)
Send Voice Messages
@borisj with automated, you call in, it says "you have 3 new messages" and then immediately says "first new message" and start playing it. With manual you hear "you have 3 new messages" followed by "to listen, press 1, for personal options, press 2, ....etc."