How many Toyotas have you owned??? ...cause I've owned more then a few XJ's in particualr and still have one in the family... I say this coming from that standpoint. I had fun in my XJ's but comparitivly they're just built to be thrash and toss vehicles IMO. My responce is also related to the fact that he will, from an engineering and quality standpoint, be taking a large step backwards from the already awesome truck he has. If he had an older XJ then yeah a newer model would be progress, but going from an 80 Series to an XJ??? That just doesn't make sence to me. ...But in the end it's your money so do what ya want eh.
I will say I loved my 4.0L's in my XJ's. Lots of torque and a great motor for the most part. Check to see if the PO has replaced the crank sensor because as I found out it can go bad and somehow fry your ECU...Water pumps like to mysteriously fry berrings too (had two of those go bad on me on ONE TRUCK in 2 years). I personaly I also liked the last gen interiors the best I think what like 97+??? They were just more polished looking and fit the truck well. I also liked the color-coded body skirts/trim on the later models. Another issue I had with XJ's though was outward view. I find it hard to see up to stop lights and they're not real "roomy" inside. The back seat is best suited to small folks and children for long drives as they will be uncompfrtable.
Oh and for the record I AM a Jeep fan... I LOVE CJ-8's, 6's and LJ Rubi's to DEATH... I think that the LJ Rubicon might just be one of the best 4wd's ever offered in N.America. I like the Mid-W/B rigs clearly as well, I find a little extra W/B like my 4Runner or an LJ/CJ8/CJ6 helps ALOT in a variety of terrain
Cheers
Dave