I think semi-slicks rule, but they have a very narrow range of conditions. They work awesome in hard/medium pack, but when things get muddy or rocky... they just SUCK. I've had to ride them in the rain a few times.. and they absolutely suck over wet rocks, roots, and mud in general. The only positive thing is that they won't load up. If you ride on the street/hardpack alot, I'd deffinitely recommend a set of Michelin Jet S semi slicks.. they're awesome. They really corner quite well for a semi slick. Very predictable as long as you run them in the right conditions!