The battery backup ones that did fail where due to one home owner that like to tinker and he "readjusted the switch" where it turned on a bit to late. The other home owner got an alarm that their was a problem with his 6 year old battery so he just unplugged everything.
The only unit I sell now is the PHCC 2400, it comes with everything a home owner needs, and they are super reliable. Now as an alternative to the Glentronics back up system, I will never install an AuqaNot. I will install the SumpPro with a pair of Zoellers or Hydromatics on an alternator.