Anymore info on spec?
Both are good vehicles and not really a million miles apart. The D2 however was a good evolutionary step forwards. So it has better NVH (noise, vibration & harmonic) reduction, more refined, more comfy and better on road performance. With generally equal or better off road performance.
Mostly pretty solid, although the newer tech comes with new issues, but then many of the older issues from the D1 aren't present.
Td5's are dynamically better than the Tdi's. Smoother, quieter, more refined, more powerful and faster.
The 4.0 V8 is mildly improved over the 3.9.
Gearbox has electronic control and in low range locks the torque conveter, so gives more engine braking.
ACE (Active Cornering Enhancement). Is optional, but brilliant. It's a reactive hydraulic anti roll bar system. And really does reduce body roll.
Rear air suspension (optional) makes for a better tow car or hauler.
Split control climate control.
New body, new chassis, different axles and rear suspension.
4 wheel traction control is very good.
Most D2's don't have a centre diff lock and rely fully on the TCS. For serious off road use this can be a downside. Some, but not all D2's can have the centre diff lock mechanism added, others will need a different transfer box.
The rear suspension uses a Watts linkage instead of an A-frame. Better road manners, but not quite as much flex for serious off road use, however ample flex for normal green laning type use.
Chassis more prone to rot, body less prone to rot than a D1.
Less wind noise, but can have tendency to leak water via sunroofs and windscreen.
The TCS and electronics, including air suspension are all points that can have issues, but mostly are simple to sort.