But Polanski's case is perfect to discuss this. Because he was arrested when he came to the Zurich Film Festival and the reaction of the cultural establishment was exceptionally fucked up: Yes, he did rape a young girl (anally, too) but he's such a good director and that's basically more important than the wellbeing of a young girl. They didn't of course say it like that, but that was the gist of it.
He was in jail for quite some time and then he was under house arrest in Gstaad for several months, while his case went through the justice system. He finally wasn't extradited because the USA failed to deliver all the necessary proof and documents. And yes, I totally believe that the Swiss Ministry of Justice didn't decide on the matter lightheartedly, because there was much at stake.

So, the causa Polanski isn't really a case of extradition or not but of the US judiciary system being unable to present a good case. They simply fucked it up.
Here's the official press release