As far as I know, the following are the important things you have to look for:
1. What is the experience of the surgeon in treating hernia and what are the complications he has gone through?
2. How successful he was in overcoming those complications and what exactly was the success rate
3. How experienced he is with the usage of various implants/meshes and what the success rate was
4. Of the cases he has handled, how many have got a recurrent hernia later, and what were the reasons
5. Does he share the patient education documents that come with the products (implants/meshes) if any of them is to be used?
Well this shouldn't be all, but this might give you an idea.