I absolutely love this vest!The battery back is a bit heavier than I expected, but still quite small, and is in its own inner pocket. It holds enough charge to use the vest for a few hours on medium power. So far, I've not needed to have it on high power, and even medium is too much most of the time. With the reflective lining in the vest, sometimes I don't even need to turn on the heat at all, or can turn it on just for the burst of heat, and then turn it off for a while, so I can go a few days between charges. That being said, the coldest it's been this year is about 20 degrees fahrenheit, and the average temp I use this in is probably about 40 degrees F.I appreciate the adjustable elastic cord in the bottom hem, to keep the cold air out. It works great under my fleece jacket or a windbreaker, to keep from having to wear a bulky coat in the winter. It feels durable, although I have not yet laundered it. It has a nice, smooth zipper. It's a longer hip length, so it sticks out under my jackets when they're zipped, which is a little awkward looking, so I'd probably be interested in a shorter version, if they ever make them. The pockets are generous, and it heats up in front of the pockets, which I love for cold hands. The elements in the high neck keep me comfortable during walks on cold, windy days. I'm happy that I bought the vest version, so I can wear it just over a long sleeve tee, with or without a jacket over it, for more versatility in our changeable PNW climate.If this vest ever stops working, I'll be looking to buy another one.