I agree that BS is a bit harsh. However, I have owned the E46 and E90 sedans and my parents have the F30. The X1 does seem tighter door handle to door handle (evidenced by the middle console & cup holder design).
However rear passenger space is on par with the E90, better that the E46, and worse than the F30. If you take advantage of the additional headroom of the X1 and raise the front seats up, IMO the rear passenger space may be a tad bit better than the E90.