Huw
I drove both before deciding. I have no doubt the Sorento deserves its praise for towing but I did not like it at all solo. Very choppy harsh ride and thats before you hook a van on it! Also a bit dated looking now in my opinion.
Santa Fe was an altogether different story. OK it is not fulltime 4wd but you don't need it 95% of time and that is part of reason for the poor mpg on Sorento. Santa Fe drives like a car so I went for that. I got the CDX7 as it has the self levelling rear suspension. 5 year warranty is a clincher. I am extremely pleased with it and would definitely recommend over the Sorento. I get between 36 & 38 mpg solo & 28 to 32 tugging. I run a pastiche 520/4 so you will know they are not a light van. No trouble maintaining 68 mph in france.
Two niggles and they are not complaints. Gearing is perhaps marginally high so you have to use 4th on long uphill drags. But I had a Frontera before that went uphill and down dale in 5th. Also the radio is a cheap naff thing with no RDS or TP.
hope this helps.
DavidC