Using my laptop, 15" 3840x2160 @ 125% Windows 10 using http://windows10_dpi_blurry_fix.xpexplorer.com/
Hopefully once I move I'll get one of the 40-43" 4K monitors - then should be able to run at 100% scaling instead of 125%. I like to be able to have multiple windows visible at once. plus tail -f log files is easier when the whole line fits on one line.
Resolution is king. I had 2x Dell U3011 2560x1200 as that was the highest I could get, then swapped those for a single Dell U3415W 3440x1440. Single High Res is best for me.