Competition is heating up in the stair lift business. Companies offering battery operated stair lifts are mud slinging competitors who are offering plug in style stair lifts. In the past year, suppliers who were preaching about the advantages of the plug in style, decided to start offering a battery operated version to counter the criticism from the manufacturers supplying the battery stair lift models. Batteries tend to be more problematic over time.
They must be eventually replaced with an added cost to do so and a time factor where the lift will be down until the dealer has come to change the batteries. Criticism of the plug in style stair lifts has usually been centered on the fact that if the power goes out, then the lift user is stuck. While this is true, in reality, the power rarely goes out in most homes. The real comparison is how often the battery powered stair lift fails over time compared to the plug in style. There is no question that the plug in style fails less often than the battery operated style stair lift in the long run.
Also, one must keep in mind that the battery operated stair lifts still require electricity to run. If the power goes out, then the battery operated stair lift will only run up and down the stairs a limited number of times before it requires electricity to re-charge the batteries.
I guess you could compare this to your furnace or air conditioner. They are a plug in appliance just like your fridge, stove and dishwasher. If the power goes out, you are out of luck with all these items. The ideal stair lift is a plug in style that has a battery back up. The extra cost of this type of model is questionable in most applications, but it is something you might want to consider.