The Jackaroo is an underrated 4wd that never sold as well as it should have. For a medium size car they have quite a big interior. The 3.5 V6 is more than up to the task and sounds sweet with a sports exhaust fitted.
The coil spring back end has good suspension travel, but the torsion bar front end only has limited travel, no worse than any other car in it's class. 2 inch suspension lifts are relatively cheap and readily available.
Drive lines seem to be very strong, club member Corey had a Jackaroo before his current GU, any one who has been on a trip with Corey and his Jackaroo will tell you how hard he drove it. It took years of abuse before the front diff eventually let go.
Aftermarket suppliers like TJM and ARB have a good range of accesories for Jackaroo's.
I would also consider the 3.1 turbo diesel engine, not as powerful as the 3.5 petrol but plenty of torque and more economical. Finding a low milege one might be an issue.
The later 3.0 turbo diesel has heaps of power but has reliabillity issues.
With Jackaroo's no longer in production and their limited popularity, the supply of spare parts may start to dry up in coming years which will also push up prices.