Is that because it can actually end up closing off career pathways?
Partially, but the main reason is my overall earning potential suffered. The extra five years I spent in school after the masters were five years without a paycheck or the wonderful effects compound interest has when started early. The difference in salary between an M.S. and a Ph.D. never made up for the loss.
One the plus side, I can actually use the line "Trust me, I'm a doctor."
-Blast