I had the 27 but exchanged it for the 23.
I like the 27, but the 23 is much sharper and faster, and I prefer the wider fov.
For $200, it's a very good value, but I decided to use the $200 towards the 23.
The 23 hasn't come off the camera since I got it.
I still like the 18 for the smaller form factor, but it seems my best images come from my 14 and 23.