I bought one in July after returning from an out of town trip and not being pleased with how the chicken sitter handled things.
First, let me say that in general I am very happy with it. We can now go out for dinner without hiring a sitter and I don't feel guilty for not getting up with the chickens.
At the time, they did not offer any electrical backup, but they would supply a solar panel and 12V battery for $45 additional. I opted for this. After about a month of trouble free operation, the door becam erratic - not opening all the way, etc. We checked the battery and it was only registering around 7V, obviously, it wasn't charging. Turns out the solar panel provided was only 2 watts so it needed to be in full sun for a lot of hours to keep it charged. I ended up buying another solar panel (more watts) and battery and they work perfectly. Our hen house is not in full sun for the entire day so now that winter is upon us, I had to do a battery swap this week. So I just keep a spare battery charged up and if we are going to be out late or out of town for a night, I check the voltage on the battery to make sure it is adequate.
The door is very easy to program, but you do have to do it in sequence - morning, then night - there is no way to tell it "this is the morning setting" and "this is the evening setting". So, if you come out in the morning, notice the door didn't open fully and do a battery swap you just have to open and close manually that day and do the reprogramming the next day at the right times. That is assuming when you discovered the door not opening fully, it is probably past the time you would normally let your chickens out.
So, in retrospect, I am happy I bought the door but wish I had not purchased the solar panel and battery from them. Of course, I am using the battery as a backup but the solar panel seems to be pretty worthless. The trickle charger that the other poster mentioned also sounds like a great idea.
Hope this helps you in making your choice.
