I've had a BAH thermostat for a year and a half now and it's performed flawlessly. I've yet to see someone who actually had this particular unit say anything bad about it. Those comments always seem to come from someone trying to sell you something more expensive.
If I understand what you are doing, it's pretty much defeating the purpose of having a thermostat to begin with. Like any other piece of electrical equipment, you need to use common sense and keep an eye on it from time to time. This is true even if you invest in a Helix thermostat.
The BAH has a green light to indicate that it's plugged in, and a red light that indicates it's powering the pad. Place the control unit where it is visible, and take a look once in a while. The red light should be flicking on and off if it's working correctly. You can also place a thermometer so it's always in the tank where you can see it easily. Hope this helps allay your fears somewhat, and good luck with your thermostat.
Scott