While I totally agree that the type of tire -to- the type of conditions is very important; what is more important is that a tire choice should not give you a FALSE sense of security. Brand XXX Super Tire of Super Grip is not going to save you from XXX unforeseen road/trail hazard. If buying a specific tire is giving someone a sense that they "can do it all" that may sound good, but too much "can do it all" attitude will show you "it all" includes things you didn't intend too. “Can do” is not the same as “should do.”
If you have knobbies so you can ride trails great, but tires are only one part of the equation; familiarity of the trail, appropriate speed, skill, weather, and proper protective gear are just as, if not more important than the tires. Do not give tires more value then they deserve! Yes, some have better grip, others last longer, or are better for specific conditions; (Battlewings cannot do mud! They are great for gravel) None of them can prevent the unforeseen, or just as importantly prevent you from doing something you shouldn't. Hell, sometimes the “bad tire” is safer than those Super Tires of Super Grip because they will hopefully limit what you think you can do with them.
Personally, I do mostly road with some dirt/fire roads and I’d rather get more, many more, miles on the road than a few more MPH on the trail. That said, I have taken the S10 to get baptized in sand and mud shortly after getting it and had the wrong tires, Battlewings, for the conditions, both deep and slick mud. I learned quickly that the limitations were not just the tires on the bike, but also its’ and my weight; 650 bike + a 250 rider. If I had had knobbies on, I think I would have just ended up getting stuck in a place I wouldn’t have been able to get the bike out of myself. As it was, I put it down & pick it back up by myself more than a dozen times on that adventure, all from a stopped/stuck placement just to put sticks under the tires (old jeeper trick) or lever it around a rock/tree stump that it got hung up on. Someday, maybe I’ll put a vid or 2 of it on you-tube.
The tires I choose…
On my bike I switched to Michelin Anakee 3s because they have a good combination of features (for mainly street riders) and I trust the brand to not have many flaws in construction, easier to balance that way too. They also remind me not to go to close to mud.
On my Jeep I use Pro Comp Mud Terrains, hard knobby like tires, because hard = less punctures, the fact that they last forever on the road is just a bonus. I’ve found punctures (both on treads and sidewalls) to be more of a threat then reduced grip on off road tires. Also tires can be aired down to add more grip.
I’ll follow the jeep’s guide on the bike when/if I get knobbies and just ride conservatively on the road with them.