I can only offer you my own personal thoughts on this question. I don't know that I have any actual experience to back this up, because once we're done with the application for a pardon, we don't see the person any more.
My feeling is that whenever you marginalize someone in society and take an opportunity away from them, you're creating a situation in which it's much more plausible to assume that they're going to return to a life of crime. Beyond that, my objection to the three strikes rule is that it just seems like an arbitrary number. I have a very tough time supporting legislation that's built around a baseball metaphor. Why three? Why not four, or whatever?
As I said in my presentation, I think affording someone at least the opportunity to apply for a pardon when we're under no obligation to grant it is really the more sensible way to go.