I've had Vaja flip cases for both my iPhone 3GS (handed down to my wife a few years back) and my iPhone 4. The cases are expensive, but worth it. They look and feel great and offer protection. My wife and I both got iPhone 5's this weekend and she's bummed out about having to wait for Vaja to release their updates. The cases keep the phones looking like new. She throws hers in her purse without worry of scratches, etc.
They do add to the weight and footprint of the phone, which is why I stopped using it on my iPhone 4 after a year or so. Nothing wrong with the case. I still use it for travelling. But with all the examples of the iPhone 5 easily getting scratched, I might re-think my case-less iPhone 5 for everyday use.
Definitely recommend Vaja.