Any 4x4 car can be fun only if you are planning to do some rock crawling or serious (slow speed) offroading. Other than that they can do straight lines at slow speeds. Cars like the Porsche Cayenne can do some offroading but would you really want to take a 100k€ car to muddy offroading?
To be honest, SUVs and slow&big 4x4 jeeps and etc. are one of the stupidest ideas for a racing sim. 4x4 cars built for racing are different thing but some standard "Pajeros, Landcruisers, Nissan Patrols, Land Rover Defenders" make as good as rallycars as tennis balls.
Why? Very high center of gravity, underpowered, ultra soft suspension... I mean, I really tried to come up with at least one good reason why to have them in LFS, but... Screamer 4x4 shows pretty well what you can do with such cars and what not.