Alan
You can probably interpret the following ute information for your wagon. It is a bit tongue-in-cheek but with the wagons I think the only choices (apart from trim style) are the engines as the Toyota and Nissan look the same, drive the same - very good - and if you sit in them you have to look for the name on the steering wheel to see what you are driving.
I have had Patrol utes as my everyday car for several years with the odd Landcruiser thrown in.
Apart from a 105 Landcruiser wagon a couple of years ago which I kept for 3 months because it was unbelievably gutless with the non-turbo engine unlike the old petrol 80 series quite a few years back which was great.
The thing I like about Patrol utes is they are so much nicer to drive than a Landcruiser ute. They ride and steer very nicely while the Landcruiser is like a truck to drive. The other Landcruiser downside is the narrow track and they are very skittish at speed on gravel roads, particularly when loaded, compared with the wider track Patrol. We rent a Landcruiser every year for the Postie Bike Challenge outback rides so I get to do 5/6,000 km each year with the latest model, about 1/3 on dirt. I have had some exciting moments with a 500l fuel tank and three postie bikes on the back.
As you say, the 4.2 Nissan engine is a beauty and I was a bit wary changing to a later 3.0 because of power and reliability doubts. I was in for a bit of a shock as the 3.0 engine has considerably more power than the 4.2 and they really get up and go. The fuel consumption is probably 20% better as well. If you look at the torque curves there is nothing in it either although the 4 cylinder is achieved at higher revs.
The 4 cylinder Nissan engine family got a well deserved bad wrap when they first came out in the GU and Navara with timing chain failures, hence the "grenade motor". Nissan solved the problem by redesigning the engine within a couple of years and the mean-time-between-failure is now slightly better than the Landcruiser (both are very good). You need 2006 onward. People like to mouth off about the Nissan engine perpetuating the myth without knowing they are talking about a completely different animal.
The Landcruiser V8 was an absolute disaster when it first came out with hundreds of brand new vehicles having engines replaced for failure due to oil problems in the first 50,000 km yet we don't hear what a pile of junk they are. Their fuel consumption is still atrocious but Toyota fixed the problem the same as Nissan.
There are as many Patrols out there as Landcruisers with 400,000 km on the clock and still going strong.
Both vehicles are tough, reliable machines and apart from the above comments it is a bit like the Holden/Ford argument.
My opinion only.
Lang