The finale absolutely blew my mind. It left me feeling, ahem, gutted. Honestly, I'd anticipated the first surprise reveal for a while yet it was still shocking somehow. The second surprise reveal I didn't see coming at all and brings up so many questions and possible story lines for season 3.
I thought the first season was great television after it trudged through the first few episodes. The second season, however, is a masterpiece. Even the weaker episodes (Will's trial, ManBearPig) were still better than most of what's on television. Bryan Fuller has definitely been studying at the school of George R.R. Martin.
If that's the case, then I don't even need to watch the show to know that I won't like it. Anyway, Grimm is good enough for me. I rarely watch back-to-back shows.