Crack is significantly more hardcore than salvia. Also, no I haven't.
I'm not really sure... I agree that cocaine is much worse for you, but as far as comparing the experiences of salvia to those of cocaine... I would say salvia has a much more intense peak, but dies out very quickly (it's about the same as smoked crack and about 10 mins less than snorted coke). I mean, a massive peak on salvia will have you seeing so many hallucinations that you can't even see anything really happening around you, whereas a massive hit of coke will have you a.) overdosing or b.) feeling really euphoric.
Though, I haven't done both of them, so I can't truly make an accurate judgement. (And I'm not willing to dabble with one in order to be able to do so.)