Pros
The company is making lots of money so they're growing rapidly. From a technology standpoint it's much better than working in a private practice, but I'd be willing to give back some of that technology if the practice treated it's patients and employees more like a private office. There are some great people that work there, but they aren't in positions of power and can't affect much change. The headquarters in Irvine is new and fancy, like a cheaper Google-like knock off.
Cons
The benefits used to be a real highlight, but in recent years they've brought in very high deductables and the quality of the network of docs available has gotten much smaller. Managers have financial goals that drive everything they do, at the expense of the patients the company swears they hold in the highest regard. There are a few managers that are good, but most are terrible at managing people and end up chasing good employees out. The manager role is not easy either. There is basically no work/life balance. Office managers come in early and stay late. Those not willing to commit like this don't last long. There are several managers that should have been let go years ago, but because of their buddy buddy relationships with the higher-ups they're allowed to stay and continue to demolish their offices/departments. Because of the rapid growth, many doctors they promote to owner don't have the patients' best interests in mind.