[arcanus]

I had a similar experience to rubidium. (Texas Ph.d., here, although in computational science, not a vile experimentalist ;) )

I've seldom seen an argument suggesting that the pay between Ph.d. and masters is substantial, or even advantageous (on average). Ph.d. is about becoming an expert and leader in a research field. It is not about the $$ or ROI.

On the other hand, in terms of career options, the differences are often quite substantial. Ph.d. is much more likely to be in a small research team than in the line of fire for a deliverable. Much more likely to be working in a laboratory somewhat independently/autonomously. Because of the predilection towards independent, high-risk/reward work, I have seen some recruiters and VP/engineering who are hesitant to add doctorates to typical engineering teams, as they gravitate towards different sorts of problems.