I've been happy with my credit union's fraud prevention and detection (which is outsourced to some company). Sometimes I'm 100 miles from home when I spend about $800 on electronics at Fry's or Microcenter. (The datacenter is 100 miles from my house, for now.) The transaction sometimes returns a "call to verify" code. The merchant COULD call, they are supposed to, but most cashiers just say "it didn't go through". This is a training issue on the merchants' side, in my opinion.
At the same time that the cashier is saying "it didn't go through", my phone rings. It's the fraud department calling to verify the purchase. The cashier re-runs the card and it works fine. It seems to mainly happen when buying from an electronics retailer, as I also remember the same thing at Best Buy. I'm fine with that. I know that if a crook gets my card, the bank is watching out.
Occasionally, they'll call about an internet purchase or some other purchase after it happens (fraud detection). It's quick and easy to verify the transaction.
I used to do another type of fraud prevention and detection, not directly related to credit cards, and I know our false positive rate was under 0.1%, probably under 0.01% - we stopped at least a thousand fraudulent instances for every one we declined in error.