Not a hard choice.. If your willing to pay up.
IMO, the patrol is pretty much Your best bet. If you can find a coil 4.2, preferably turbo you cant really go wrong. Very solid car out the bush. Rides great, its just a pity they got rid of the 4.2 (post '06 i think but feel free to correct me on that) cause it was a machine.
For 20k you should be able to pick youself up a very neat GQ wagon or a GU possibly.
*NOTE* I'm not sure if this is the case with the wagons but i know not all of the GU utes are coil all round, some have a Leaf rear end. Just something to look out for. Although if you do get your heart set on a patrol they are considerably cheaper.
As for the cruisers welll...
Are they cheaper? Yes. Do you get more value for money? No, not always.
Presuming your talking about the 75 series, being leafs all round they are much stiffer, have less 'flex' (without some fairly major mods), they do not have an LSD in the rear which is a real bummer if you plan to do much 4wding and have an all round less comforatble ride. This being said i have had some mates who have owned them and they have got most of the places our patrols have gotten, although they were given a damn hard floggin to get there, and the passengers needed to visit the chiropractor after just about every second trip!
In the end it all comes down to personal preference and how much of your hard earned dosh your willing to cough up. Sure, if you have got the money to spend on serious suspention mods, you can consider a 'cruiser, but untill then you gonna be a little more comforatable in your stock Patrol. And dont you dare compare a (gut) lux with either of these two fourbies!
Anyway theres my rant for the night. Might retire to the couch for a little while now
Edit: I dont suppose your in Victoria are you mate?
My brother is selling his GQ 4.2TD coil ute if your interested