We had a small group (about eight) for Poison Spider yesterday and beautiful weather. We remembered our trail leader from the very first trail we ran in our new-to-us Rubicon at the 2011 Chili Challenge - we've come such a long way since then (just empty every pocket.)
This trail is certainly no harder than a 3.5 if you take the easier lines and/or bypasses and if you take the harder lines then the difficulty gets bumped to maybe a 4.0. My buddy Don was in front of me and I followed him for the entire day on his lines (for the most part) except for a very steep optional wall descent - I think he slid down the last six feet and hit bottom so hard I watched his rear tires bounce off the wall about half a foot. Don said "that caught me by surprise - I've done this one previously - it's way more undercut now...I should have looked it over first...". We backed up and went a different way 8) .
Later in the day on our way out we had quite a traffic jam at the sand dune area - dirt bikes, side-by-sides, full size vehicles, you name it and it was there.
I really liked the obstacles on Poison Spider but most of the trail was a rocky and rough ride, don't think I'll do this one again.