Thanks guys.
I hear the consensus on the blue tint.
Yes, this used HD Cache. I went for all-default settings and was very happy about how these worked. No tweaking at all and very fast renders. Perhaps slightly soft GI here and there but altogether very satisfying.
No bug. One problem only, but not sure it's a bug or my doing something wrong. I originally had a leather material on the long chair. Very blurry reflections. It seemed to get "dark" underneath the main highlights. As if the highlights were somehow influencing the diffuse. Very strange. It's the only time this happened. It was only on this model, but I checked the geometry, the normals, etc. Couldn't find anything...
It could be the hybrid glass bug... which is known. But i am not sure how it could get propagated on something like leather material.
Only thing you could try to tweak is GI/AA balance parameter. When lowering it from default 16 to say 8 or 4, it will focus more samples on AA, rather than GI. That will clean up shots with strong Depth of Field faster.
So as a rule of thumb:
Regular shots - keep at 16
Shots with subtle DoF - decrease to 8
Shots with strong DoF - decrease to 4
EDIT:
This is the screenshot of a known bug. If you enclose light source in a Glass with disabled caustics, and this combination is being reflected by surface with low glossiness. It creates a problem.
I will try to find out some plausible workaround.