I ordered a used NU25 directly from Nitecore. It arrived a couple of days early. And just in time, too, because that night a wind storm came tearing through our neighborhood and knocked out our power the next morning. So the light got a 36 hour trial by darkness.
And it's a champ! It's light, comfortable, and easy to use. I've never used a shockcord type headband before, but it was great with a hat or without. It's so light weight I didn't mind having it on for long stretches while reading. There's a very short learning curve for the UI, but it's quite simple. All I really needed to know was double click on the right to go directly to the ultra-low 6 lumen setting, and then additional clicks take you through low, medium, and high. All I needed was the ultra-low because it's perfect for everything I need to do around the house and for reading. I could also have it tilted all the way down and my glasses didn't catch any glare. It's also easy to go directly to the red light with a single long press on the left button.
I used it for quite a while before I had the opportunity to recharge it. The battery was still nearly full.
I am very happy with this little light. It will be going into my main pack to go on every trip. And it's so light and small that I won't mind it coming along.