re: When do you value pension benefit vs pay?

If your current salary minus the new salary is enough to get the same benefit by investing in 401K or IRA, no.

If vesting in the new job is too long, say 7 + years, then no. I worked for 33 years professionally before I retired and was only vested twice out of nine different employers. Some I left because me job was cut, some I left because I didn't like it anymore.

All a pension is is a retirement account that someone else manages for you and you have no control over how the money is invested, or usually even knowledge of it. I prefer to manage my own investments.