Below is screenhots comparison for shadows on "ULTRA" on 13.12 vs 12.2 live.
Same place, same gamesave and in-game time, but fps is 30 vs 60 (literally!).
New shadows on "Ultra" seem to be infocused (notice they has less brighter "outlines" around them). This new shadowing algorithm seems to cause massive fps drops (and really blurry outlines for shadows).
So, ultra shadows, 12.2 live (60 fps) vs 13.12 (30 fps) below (performance stats included now):
http://www.framecompare.com/screenshotcomparison/FECF1NNU
Old comparison (without fps and stuff):
http://www.framecompare.com/screenshotcomparison/FE22CNNU
Shadows on "High" are noticeably more blurry on 13.12 vs 12.2 as well, but at least they don't seem to tank the performance (I got 60 fps for both 12.2 and 13.12)
http://www.framecompare.com/screenshotcomparison/KGPZLNNX
Devs, please fix this! We want shadows like they are in 12.2 (both look and performance wise).
P.S.: Temporary solution for those playing on 13.12 - set your shadows to "High" for now to get decent fps.