The blue in the stone (and the tiles) as well as the walls are not quite right with the lighter blue/gray floor. You are getting a clash of undertones with the lighter floor. That means you have to move away from the "close but not close enough" colours and go with a complimentary colour...which means the brown will be a more appropriate colour.

It does NOT have the blue/gray undertones...therefore it doesn't have the "wrong" undertones for the project. The darker brown will warm up your space and anchor the project.

If these are the only two options, then the brown/darker floor is the better option...but there could be better choices out there that you didn't take photos of.