we have one. i LOVE it.

i'm home alone during the day. so it makes me feel safer. plus the fact that our entry is downstairs.

i like being able to hear the chime when the door opens. weird..but for me it's like a "honey i'm home". but i have had it go off at the "wrong" time of day. the door didn't get shut enough and it blew open. and once the maintenance man tried to come in without ringing the bell.