I have kept my old style X5 because it is the perfect size for the job and has proved so reliable and cheap to run.
I had it converted to LPG after only 1500 miles and it has been exceptionally cheap to run ever since : The fuel cost has been the petrol and Diesel equivalent of 35mpg with lower emissions.
But depreciation has been absolutely crippling : £46,000 down to a current value of less than £10,000
The new X5 is far too big and expensive. The X3 is too small and just plain ugly.
Nobody else makes a 4 x 4 that is good at what it does.