I can't really compare the BAFX against any other but I have had it for about 4 years now and haven't had a problem. I leave it plugged in 100% of the time so it's ready whenever I need it.
Not really as simple as the app finding the HBATT sensor, but almost. When you configure the gauge, I selected advanced (or was it extended?) sensor list and had to scroll around to find it. Once selected, the gauge will appear and you can arrange it on the screen as you see fit.
I used the Torque application on my android phone to read Hybrid Battery % and have seen a low of 42% (when the ICE kicks in on level roads) and 70% (when coasting down a mountain grade).