Horizon's are bomber. Pretty thick at the tread so crazy long mileage possible (esp. if you rotate front/rear infrequently). Sidewalls can be a bit fragile but I guess this it what gives them their supple ride characteristics.
I'm a couple of months on the new Gravelking+ and no problems. Added p*ncture protection seems to have answered previous Gravelking failings with minimal weight increase (approx. +40g vs. std) and no discernible detriment to the riding characteristics (still plenty fast and comfy).