I decided to bite the bullet and got the 12mm f2 lens.
Thoughts so far, even with the touch to focus function sometimes it focuses on the wrong thing, I bet this is due to my fat fingers.
ISO 3200 at night in east coast park sucks. I don't use flash so I guess night photography is a big no no especially on things that move. But ISO 3200 on my 550D was not usable to me too. Most I went up to was 1600 on my 550D before I felt the photos were ugly.
I still am not used to not having a viewfinder, makes it harder for me to compose, I feel that my photos are not as 'nice' due to the composition.
However it's small so it is alot easier to bring it out, and I am having fun with the filters !