I obtained a 13" 3200x1800 laptop (works out to about 300 PPI) for the purposes of testing our product on such devices. Because we were modifying our software to work well on such modern hardware, my experience was probably not as great as yours (it's better now, but still mot perfect).
The worst experience is on hereogenous multi-monitor setups. Most software behaves very badly when a 22" 96 pixels-per-inch external monitor is connected to a 300 pixels-per-inch internal monitor. A lot of stuff is badly written to always assume 96 pixels per inch (which was never true anyway) in order to render 12-point type as 14-point type at 20", for a perceived 12-point type at 12". Our design department's take on that was to have the value of an inch vary according to the display device. Idjits.
Anyway, I'm old, my eyes grow dim, and most default settings on the HD display are too small. I want 12 point type to render at 12 points regardless of the pixel density, and I want a GUI to scale appropriately. Anything that's using pixel coordinates is broken. I don't want my external monitor scaled up at the same rate. I'd give most software a couple of years before it works well on today's hardware.