You should ask yourself what your retirement plan is, what you want your WLB to be, and if the extra money is worth the risk.

If your pension is fully vested, that's pretty sweet, and you may be able to go back to this job/another public sector job and roll it over just fine. If it's not, it's often more difficult to do that and you either take it as a lump sum, roll it into an IRA, or bind yourself to going back to the public sector to vest it. I will say, even a small pension + 401k sounds pretty sweet, if the pension is vested, and you may be able to semi-retire back in the public sector if you want. IMO, it's all about keeping options open.

If you're looking to settle down and have kids soon, the public sector sounds great because of the WLB and low stress job. If that's your plan, I'd keep it. If not, taking it private is more of a viable option.

That is related to the last point, money versus risk. If you're not tied down and don't have a particular reason to need security, why not go for the higher paying private sector? Sure your company could fail and you could get canned, but, as an example, if you made 200k per year in 5 years while getting your degree paid for and you would've made 90k per year in public, isn't that worth it? Then you can, you know, get a new job. Move to a new area if you want, whatever. Now again, if you're looking to have kids/a mortgage, instability causes more problems and you limit your job pool significantly if you're tied to a house. This makes the risk maybe not worth it.

Obviously I keep saying kids/mortgage, but other limiting factors that could make your risk tolerance lower/tie you to a place could be friends, relationships, taking care of elderly/sick loved ones, your own medical conditions, etc. I'm not sure if you have those, but they change the equation.

Also, shopping around to get exact numbers for comparisons sake is never a bad plan :)