I had the exact opposite experience with Toyota and deem the X5 to be 85% as reliable, 100% as capable off-road, and 150% better at on-road driving.
If you rid the pressurized cooling system with waterless coolant + a different BAR cap, and the engine isn't near 100K on the same seals & timing chain guides, you're more than golden.
I post these same 2 videos all the time
These are standard crap tires on a very
steep slope. It may not look that way in the video but it's steep and slippery. I've had a hard time getting a lifted 1500 Silverado on muds getting up a dry slope at equal grade
These are low pro tires wading through a river with the water level reaching the intake
With a little work the X5 can pretty much go anywhere, however I'm not sure about how good the rear bumper clearance is.
I get Top Gear makes Toyota seem "unstoppable", and I do know the mid to late 80's 4Runners ARE one of the best off-road platforms you can have, but it's so funny to see how much people understate the extreme testing BMW puts into the X5... It's not just a lifted 5 series with an SUV shell.