My experience is a bit different to Cyberess, with fuel economy anyway. we have an 06, (I think) and the 6 speed box is great. fully loaded for touring with a roof pod and swag on the roof we get about 12l/100km sitting on 120. 80 l tank is a pain for big trips though, I carry 45 L(diesel) in jerrys when needed. Ours is lifted, bull bar, winch, snorkel, rear wheel carrier. I drive prados and cruisers when doing remote work in Central Oz, I would be happy to take the Pathy anywhere I take them, probably a bit slower though. I have not had any trouble not having a diff lock, however its mostly rough dry stuff here, I imagine lots of uneven wet stuff would be different.
We crossed the Pentecost on GRR a few years ago, plenty deep (maybe 600mm) for a desert rat, no worries.
I have only just got a camper so I cant comment on how it goes with a bit more load.