The Paceman is actually tad longer than the Countryman, but headroom for the two-position backseat is down half an inch; the shallower hatchback slope drops cargo volume to 11.6 cubic feet versus the upright Countryman’s 16.5. Mini has yet to provide rear legroom specs, but I sat back-to-back in the Paceman and Countryman and the Paceman’s backseat is cramped in all dimensions versus the well-packaged Countryman.
Fold the front seats forward and passengers will have to squeeze through a narrow pass-through to get to the backseat. But the front seats return to wherever you had them rather than a default position that’s usually too far forward and upright. Nice.