If you get one with orange lettering on the keys, it will die within 3 months (in my experience). I sent it back to Logitech and they sent me one with blue lettering. Those are the ones that work.
I’ve had mine for a couple of years now and I love it. Low profile, good resistance, very comfortable. Even in minimal, non-direct light, it always stays charged.
I have both. My first one, with the orange lettering, still works, but one of the feet snapped off. Instead of sending me new feet, they sent me a whole new keyboard, which is the blue one. Both work great!
K750 owner here. I honestly can’t use any other keyboard (besides mechanical) now. The low profile and short keys makes typing a breeze, while also making it work comfortably in any possession.
I highly reccomend anyone who doesn’t have a high-quality keyboard to start replacing one’s crappy work keyboards with the K750.