The video quality is surprisingly good. Battery life is around an hour and maybe eight minutes at 1080p. Not tested in 4K. Two main problems, the first, very shaky, is that there is no image stabilization. Even if you think you keep your head straight and still there is still movement unless you take your glasses off and put them on a stable surface, this of course defeats the purpose of having glasses you can put on and walk around with. One of the biggest problems, which is easy to solve once you know what you're doing, is that in order to change the quality of the video and put the correct date, which defaults to 2000, you have to change the text in a text file built into the glasses on the doctor, it's all sort of explained in the instructions. But the problem is that you have to take that file, copy it and move it straight to disk. When you connect the glasses to your computer, first there is a settings folder, and then in this folder there is the init.txt file. So if you need to make changes and I'm sure you want at least the right date, type this, save, close the file, then, it's not in the instructions, copy the file up a folder up to the drive letter and paste this init.txt file there. I have written to the company and I hope they will give the right instructions in the future. But this is one of those products that comes straight from China, and the direction isn't so clear. This is the main reason I am writing this review.