I had 2 GU Patrols, both were great in the really rough stuff but my current Pajero does everything else much better - onroad, gravel tracks, mild 4x4ing, beach, comfort, towing, wife-friendly, fuel economy, power. Even interior room is only marginally smaller.
Honestly, how often do people drive their family 4x4 in the really rough 4x4 tracks? 2 or 3 times a year? IMO not worth putting up with all the negatives for that few times a year where it was awesome.
As said above the GU has its place but most new 4x4 utes/wagons can do a better job than the GU in 95% of driving situations.