Gosh, I like them both. I do have to agree with @clearday that the details pop out a little more. The color one is warming. I'm a little confused, I'm I looking up or down - I feel dizzy and turning around.
How interesting it is to look at a colour and a B&W version, and see such different things. In the colour version, my eyes instantly go to the big lights at the top of shot. Here, I am looking at the strong lines of the staircase. They are both lovely shots.