It seems we both like this lens...
I often use it for stage shots (theater, concerts), sure not because of the max aperture (performance is not that good), but because it will gracefully take spot lights in the frame without annoying artifacts or contrast drop. The 105/2.5 might be equally good in that respect, I did not compare them from that point of view lacking time & opportunities, but I know I can rely on the 105/1.8.