As I said, I am not quite through with all of them, but it is still a hard question. I really like the Stormlight Archives, though I could not name my favorite book. It's too much of a continous story for me to even exactly pin down what happend in which exact book.
Other that those I loved Bands of Mourning. The setting, the characters, the showdown, all of it reminded me of some adventure books by my favorite author from back in the days. I always wanted to reread those and now I am afaid that they really won't hold up.
And of Non-Cosmere works, I think the Legion book are be my favorite. A bit short, but all in all amazing.