Somebody say my name???
All the above posts are pertinent.
Got mine 7 years ago with 67,000 on the clock. Head gasket went a few thousand miles later and a year or so after that the bottom end gave up the ghost.
So on the original engine I managed about 9000 miles. Had a re-manufactured engine fitted from Ivor Searle which cost a pretty penny and the truck is currently at 135,000 miles or so without any mechanical problems.
As Drift said, most of my woes seem to be starter motor related and any other nonsense has been immobiliser or sensor related. mechanically its sound.
Personally speaking its not a bad engine. Regular oil and filter changes seem to be the key to longevity. Since the new engine went in 6 years ago Iv changed the oil every 4000 to 5000 miles. Takes a few minutes every few months for peace of mind.
Before the big tires went on it regularly returned 28 to 32 mpg but that has dropped substantially since. Higher diff ratios should help alleviate that somewhat.
Its torquey enough in its own way. Iv towed car trailers with big cars on the back with little trouble, approx 2.5 tonne. Slow admittedly but once at speed it will stay there. Constant 60ish mph from London to home in hilly wales with no problems.
Its been submerged completely on more then one occasion and just keeps going (having said that its probably not going to start tomorrow

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I think most of the damage to these engines is caused by over revving them. Due to the long stroke and high compression all the usable power seems to be from 2000RPM to 4000RPM. After 4000RPM there is a distinct 'rattle' from the engine, balance shafts were fitted to later models to alleviate this. I rarely exceed 4000RPM if I can help it as it doesnt get you anywhere any faster and doesnt produce any more power.
Rocker cover gaskets are prone to leaking but it takes minutes to change them and I discovered recently that the original VX gaskets are a bit thicker then aftermarket.
Exhaust manifolds are prone to cracking. Mine is cracked but I have a couple of replacements. Its just a matter of me getting round to fitting one. They can be welded but they will eventually crack again.
Head gaskets seem to be a common problem, usually between 60,000 and 100,000 miles. There may have been issues with the original gaskets as they seem to go towards the rear of the engine. It has been said this may be because the engine is tilted to the rear slightly.
Due to it being a long stroke, high compression engine the con-rods and crank are under more stress then the 2.0 litre version so the bottom ends can be finnicky.
As mentioned Gudgeon pins can wear causing the pistons to go through the side of the block, regular oil changes will alleviate this problem. VX originally quoted 10,000 miles between services. I personally think this is too many miles between services on any engine.
Timing belts should ideally be replaced a bit sooner then the quoted 36,000 miles. Say 30,000 instead. The belt guide rollers are plastic and can disintegrate in spectacular fashion. Although, having said that I went for a tad over 40,000 on mine before I remembered to change it. The bearings in the rollers were worn and rattly so I wasnt far away from breakage.
They do burn a small amount of oil (mine uses about 200ml every 2000/3000 miles) but this is largely dependent on the type of oil used and the overall condition of the engine.
Thats about it really. I reckon if you find a car thats got 100,000 miles or more on the clock it going to be a good one.