Physician Sub

I have recently interviewed for a Physician Sub position at a Plasma Center and I am interested in some feedback from anyone that works in a plasma facility. I currently work in LTC and am looking for a change. I have read some posts but they were from a few years back. What are the pros and cons? Salary I should expect I am in NC.

I am really hoping to get a job offer, but any info would be greatly appreciated!
What is a Physician Sub?