Being somewhat learned on the subject, I'll smoke a marlboro before I'll touch spice... I do sometimes smoke cigarettes, I won't touch this shit, ever. For cognitive reasons as well as cancerous ones. Bottom line is, all these are dangerous. They're mostly (all?) full receptor agonists, with danger of actual physical harm as well. You can, quite literally, OD. If you get reasonably high on them, you can feel the resperatory depression, just like with alcohol. It's a bit scary. Still no excuse to ban em'.