I personally find Candle Impression to be a more quality candle when it comes to all features combined, and I've never had a CI or Mirage fail.
I have probably purchased 75 or more flameless candles in several brands for myself and gifts, many Luminara, and have had three of those Luminara fail over time. They simply quit working. It really isn't a horrible fail rate, but for the cost, it is bothersome. One of the reasons I prefer Candle Impressions Mirage is the much more reasonable cost, longer battery life, better wax and colors and textures than much of what QVC offers in Luminara.
I rotate my candles, as I have different colors for different seasons and holidays. I dont' use the timers on a lot of my Luminara anymore as I like the remote feature so much better. I may go many nights and never be in a particular room or I may have daytime guests and wish to have all the candles and lanterns lit during a time when the timers aren't scheduled to be on. Using the remote feature allows me more flexibility (as well as not having to mess up the display to change when I want them on and off) and doesn't waste batteries because they come on when using timer mode, even when I may not be at home or may not be in that room for the time they are lit.
Depending on how you handle the candles, store them (not too hot, cold or damp) and how often you rotate them in and out of use will determine how long they last, but I'm getting years and years out of mine, with very little failure.