Just as long as you can weigh it down with water in tyres or linkage weights and have the rubber at a low psi it will work fine. We use our 8530 for heavy tillage all the time. Front and rear duals, front linkage with a 1800kg weight at the front and a 2500kg weight for the back linkage. We still have room for the draw bar to get underneath.
Couple of farmers here use them for ripping and other heavy tillage. Not sure of ripper sizes, somewhere between 6-8 metres I think. One in heavy clay soils (cotton) the other in hard as cement red sand (spuds). Haven't heard any complaints. Good strong tractors, but like gav said, they need some weight to get the power to the ground without excessive wheel slip.
IVT for heavy tillage is the go. Allowing full power at all speeds and minimises slip, when a power shift changes it can shock the system and have a small effect on wheel slip. Between our 8530 and 8360R we have 9000hrs logged up. The 8530 has close to 6000hrs without a problem. Just wish they where 10-20cm higher off the ground and they would be a perfect tractor