Most street/offroad tires have a soft sidewall that can help with traction(when aired down) but bad for punctures. My friend punctured 2 MTR's on Rat/Con in one day, one was NEW that had been punctured on that trail the last trip out. Good traction though. Every tire has an area where it excells and an area where it doesn't. To ask a general question about what tire is best will get you more than 77 answers for sure.
To answer an earlier question about the SX's and Iroks, I have had them both and OFF ROAD only, they are tough as nails, but the IROKS hook a little bit better for me, but are CLEARLY wearing much faster because they have (seem to have) a softer compound.
Also, what the weight on the tires and what pressure you run them at makes a bigger difference than most people think, so if you are going to compare tires be sure that they are leaving the same foot print with the same effective pressure in them or it is apples to oranges.
I run a 42" currently with around 2-4 psi in them most of the time and I am happy with how they perform too. I will buy another set when these wear out.