I don't use hidpi, so I can't really compare your screenshots. :) Mapy.cz just looks better on your screenshot to me (aside from blur caused by rendering a screenshot vs direct software rendering optimized for my LCD).
You don’t need a high resolution display to compare. Save the images, open them in irfanview.com or getpaint.net or other image viewer/editor that can set 100% zoom (with scrollbars). The hotkey for 100% zoom is Ctrl+H in irfanview, Ctrl+0 in paint.net.
Yes, my image viewer can set 100% zoom. But my monitor just displays it exactly like if I did open mapy.cz myself on a lowdpi monuitor, and the labels are thus correctly sized and everything just looks very nice, except for a huge canvas with a need for scrolling.
mapy.cz indeed has more data but visually, Google IMO looks better on my Windows PC. Maybe it’s high DPI support, maybe it’s font rendering, but small labels are barely readable in mapy.cz, compare the screenshots yourself: http://const.me/tmp/maps/mapy.png http://const.me/tmp/maps/gm.png BTW, Microsoft did even better: http://const.me/tmp/maps/ms.png