The 5L's main reliability problems are:
The MAF hotwire can get dirty, or die, causing the car to run like crap. To see what a 5.0 runs like without a MAF, simply unplug it

They have cooling system leaks. I'm finding that I have to top up my coolant every now & then, but they're happy to run on low coolant.
They can ping on hot days, but this is more due to the choice of petrol rather than a reliability issue. Or if you're like me & have a frankenMAF setup (EB sensor, AU body)
My EB has been through a fair bit of crap & I'm still on the original motor (360,000kms). Abuse they can handle consists of the following:
1) Having the oil level so low that it doesn't register on the dipstick, you have valvetrain noise, and the oil light flickers when you pull out of an intersection or take a tight corner, or when you back off at 155kph after the finish line at Heathcote
2) Driving it fully loaded up steep hills on a 40*C day with 4.11s and a 3000rpm stally... AFTER the top hose has loosened & is pissing coolant everywhere.
3) Not changing the oil for 20,000kms so it resembles road tar on a hot day
4) buuuuurrrrnnnnnoooouuuuuttttsss!!!
5) >6000rpm in 1st when missing a shift (yes... in an auto

)
6) city driving with no clutchfan or thermofans on summer nights
They put up with a lot of crap. Who else has stories to share about engine abuse?