“How common are hernia mesh complications?”

While I do not know the number, I would be aware that any foreign body, no matter how designed it may be to be nonreactive, can have unexpected reactivity per individual. If the surgeon can use your own tissue to prevent mesh use, I would definitely choose that option. My surgeon could not find enough bulky tissue to repair a ventral hernia, so he innovatively used a part of the third external abdominal muscle to fill in the "hole" and pull together the midline skin. I do get small cramps when I move a certain way that takes about 30 secs to be relieved - you may have to expect that rather than extrusion and inflammatory reaction to the mesh implant.

In my experience, the incidence of chronic pain related to mesh is relatively low, probably less than 5% and the incidence of infection is about 1%

It depends on your comorbidities, such as, obesity. The more risks factor you have for a complication, the higher the complication rate. Clarify with your surgeon or Google.