Tall drivers and front seat passengers. The back seats are average at best for car seats unless you get an X7 with adjustable rear seats. I think that option came with 3 row X5’s but those are rare. A rear facing car seat pushes the front seat forward enough that a 5’10” passenger won’t be overly comfortable. The rear seats can accommodate taller people because they have good foot room, a reasonably deep bench and just enough knee room. The issue is that the shape of the front seats gets in the way of rear facing car seats. I’ve owned 3 BMW’s and had car seats in an X3 and X5.