A number of comments:
First, it should be noted that the Presence sensors are not real quick in terms of when you leave as well. It’s possible that this can be improved with the changes in settings that Ben was talking about, but generally I get a minute or two away from home before I get notification that my garage is closing. So when you’re talking about the double edged sword bit of extending your geo fence, you might have that same problem with the presence sensor.
Second, remember that if the sensor is checking in more often that it’s going to be using up the battery more. (Ideally it would be cool if you could specify times to check in more frequently… like 5:00-6:00pm, but then check is less often other times of day. Of course, this would mean keeping a clock on the device which would probably use more battery as well.)
Third, there are somethings you can do to help with the signal acquisition. For example, I used some command strips to stick my sensors right on the inside of my windshield up at the top. Way up there it doesn’t block your view at all while driving, and the less “stuff” the signal has to go through (car doors, etc), the sooner it has a chance to get noticed by the hub.
Likewise, if you have a SmartSense motion sensor that can be positioned in such a way as it’s closer to the road/driveway than your hub, this will help extend the Zigbee range (if the sensor is plugged in), and increase the outer range of when the sensor is seen. For example, I have a motion sensor taped into an upstairs window that faces the road. My sensor will at times trigger when I’m two houses away from my garage.
Four: The sensor coming and going is a known issue that SmartThings hasn’t been able to completely solve, but again, there are things you can do to help. This is a case where the Zigbee signal just isn’t communicating with the Hub well. The presence sensors use a relatively low powered radio to prolong battery life, but of course this limits their range. Again, a SmartSense Motion sensor, plugged in, in the garage can really help to increase the signal strength. Like wise, move your hub away from your Wifi router if you can manage it. Zigbee and Wifi use the same frequency so some distance helps make the signals clearer. Finally, I know there are some channels of WiFi that cause more interference with Zigbee, but I forget which ones… contact support for help with that.
So there is definitely some tweaking you may need to do to make this work well for you, but once you have them going, they’re pretty nice. I love just driving home and having my door open for me. And I love (using the app you referenced) have it unlock my side door, and then after I open and close the side door, having it automatically shut my garage.