Nice. I've been running the original Discoverer STTs for about 5 years and am not a huge fan, since they tend to chunk and the sidewalls are incredibly stiff. I typically air down on trail to ~ 8 psi for extra traction, and they barely bulge. I bought TMI weld-on beadlocks so I can drop them down even further.
Wonder how the Pros compare? If they're a softer tire, I may look into them...