Just installed it. Works fast. Apps are much better.
I'm surprised the system came out with translations already. There are still bits of English here and there in the OS, but most of the stuff is translated. I also didn't expect Live to work for Poland. It's a shame that Live system is fucked up, though, and because I registered on UK (when I was registering the Live wasn't available in Poland yet), I had to set up my location in Windows to UK too. Otherwise I only got an error message when I tried to run My Xbox Live or any other Live app.
For some reason Photo app doesn't want to show my photos. It imported all albums (folders) just fine, but only two of them are populated with photos; the rest is empty :/
And I'm saddened that the "glitch" with snapped windows still exists. That 4px gap between windows annoys me to no end.