I stay away from safelists myself. The problem is you are pitching to people who have been pitched to a thousand and one times before
I think building your own opt in list is the way to go. Yes it takes time and effort but the results from your own list are far greater than any safe list.
I can't honestly see the point in sending out thousands of emails if the response rate is going to be poor.
Interestingly enough, there are people paid to read emails. Makes you wonder