I have an HTC 10, too, and I like it. It's a well-made phone. First off, what's malfunctioning on it that it needs to be replaced? You should be able to fix anything under warranty. Secondly, HTC phones are built to last several years. My previous HTC was the Incredible S, and it lasted 5 years. It still runs like a charm, too, it's just a little slow. I use it for when guests visit.
The U11, with the sensors on the sides, is new technology that hasn't been proven yet. Unless you have a legitimate reason to buy a new phone, let people who have more money than they have brains be the guinea pigs.