On my X1 Thinkpad with 2560x1440 display res, they look a tad too large but maybe I'm too used to the small fonts I had. 
At least the menus were readable and usable with touch but still felt like I downsized to 1024x960.
After setting persistence and on 2nd boot the font sizes are back to the small size I'm used to on my installed version ....... something I also noticed when installing on an older x260 (with a much lower res) so I think there is still a lot of work needed, on the fonts there.
All in all no certainty dynamic fonts are going to look good in all situations after a while i.e not sure even, if this is progress or decline. 
