My ST Maxxes have definitely improved the capabilities of my car.
I drive a Great Wall 2011 Series Two X240 wagon with a 2" lift (approx) and 245/75 R16 ST Maxx tyres. These are not my first set of Cooper tyres but they are the most aggressive tread pattern I have ever had on any vehicle.
I drive on beaches and in the bush and love a bit of technical 4wd'ing, especially on rocks, but within the limits of my vehicle and experience level. I avoid mud where possible, i.e. those big mud holes that some folk love to dive into with their cars. Mud gets into everything and causes damage so... I'll go around it if I have the choice.
I drive around the Glasshouse Mountains a lot as it has such a huge variety of terrain and surface conditions and my ST Maxxes have definitely improved the capabilities of my car. I refer to my car as "My Chinese Tonka Toy".
I generally run about 18 to 20 psi off road just to get the tyres to belly a little. The sidewalls are so tough that I need to lower the pressure more to get that result as my car is not as big and heavy as some. I have had a rat tail file embedded in the tyre and go clanking around inside the wheel arch until I stopped.
About 60 – 70mm of the file broke off in the tread but did NOT puncture the tyre. I put this down to a combination of the toughness of the tyre and the lower tyre pressure. Whatever shortcomings my car has, it certainly isn't the tyres.