The only thing I do find annoying with the X5 is the lack of spare tyre when you order third row seat.
The wife loves it and I honestly prefer driving the X5 to my little 330i- one of the reasons why I won't be getting the M3 but the X6 as a replacement.
Back to the lack of spare tyre, I believe if the engineers had thought hard about it, they would have fitted one in the boot and still accomodate the third row seat.