If a monitored door or window is left open when you arm the system, Ring Alarm will warn you, but give you the opportunity to push an illuminated button on the keypad to bypass that sensor. You’ll get a similar warning and opportunity when using the app to arm the system. The sensor will remain bypassed until you disarm the system again. It’s a convenient feature: If you left the upstairs window open, for example, but are in too much of a rush to run up and close it, you can take a calculated risk and secure the rest of the home.
Third, Nest Guard has a voice. Of course, it’s no Google Home, but it will provide useful information. For example, when you arm your system, there is an arm delay which allows you to exit your home without setting off the alarm. Instead of an annoying beep that continues until the system arms, Nest Guard uses a friendly voice to tell you how much time you have left.
Ring Alarm hits nearly all the right notes for a basic DIY home security system. I’ve already touched on a couple of its shortcomings—including an absence of support for smart speakers—but tighter integration with Ring’s own cameras would be another welcome development. When an alarm is tripped, the cameras should begin recording to perhaps capture a glimpse of what triggered it—potentially valuable forensic evidence you could provide to the police investigating a break-in. And if Ring Alarm could control your home’s smart lighting, it could turn on all the lights if the alarm is triggered after dark, which might convince an intruder to make a hasty retreat.
Update 1/24/16 - I have found a fantastic use for the Ring Doorbell and Chime. My mother-in-law, now in her 90s, lives by herself. She has become hard-of-hearing and often does not hear the doorbell. By installing the Ring on her door, she now is bothered much less (solicitors tend to recognize it and don't seem to like it) and when someone rings the bell, the Chime, placed by her favorite chair, gives her a better chance of hearing someone at the door.