My experience: procurement (strategic sourcing) is going to pay more. Also, more prestigious.

Planning: routine week by week and monthly tasks that must be completed and fit into the S&OP process. You will constantly be re-running your supply and demand plans for different scenarios. I’d imagine if you get into running the department it can be lucrative.

Procurement/sourcing: caveat, if you get into a “procurement” role that is just issuing POs, then that’s not going to pay well. Get into the supplier management side and contracting and that is where the money is it. Lots of fire fighting and problem solving required. Relationships are key. Individual contributor roles do well.

I don’t intend to bash the planning role, both are extremely important to the business. Coming from my own experience doing both and ultimately finding my way back to procurement.