Had the M7 too, absolutely loved it for 3 months. Right up until a desktop harddrive fell from a shelf right in the middle of the screen. Corner went through it like butter 😭
M8 with Harman Kardon mod (fakes the model so the controls appear) is absolutely incredible. They really squeezed everything out of those tiny tweeters. And the IR Blaster is super handy.
Mann I remember my M8. I still use it as an IR remote sometimes. Sadly the battery is pretty much completely dead so I can't really use it for anything else.
I had an HTC 10 at the time, around its release date as that was the only phone with a Snapdragon 820 available at T-Mobile in my location. It was an ok phone but got better with a custom ROM+kernel. Shame about no dual front facing speakers on the HTC 10 because the single front facing speaker actually sounded great.