BS is little harsh, no?
Obviously, opinions about space are opinions. So everyone's will be a bit different.
Personally, my OPINION about the FEELING of the X1 is that it is very small inside, in any dimension other then headroom. It feels more cramped than my E46 sedan, in fact. I noticed in particular that the front foot wells and the width between interior door handles feels tighter. The rear seat does not seem to have more room, and ingress/egress is made more difficult for tall people because the distance from the B-pillar the front of the rear seat seems tighter than my E46.
Again, these are opinions, as I haven't measured anything.