As you allude, lots of variables, but average salary in the public sector is now lower than for the private sector so thats a factor at the front-end. In real terms civil service salaries are 30+ percent lower than in 2010.
And, depending on where you go, could end up paying 15% of your gross salary into the pension.
So you've earned less and paid in more. Its an expensive free lunch, not the gold plated gift the Daily Moan would have you believe.
There may be other unexpected benefits, dependent upon where you end up. For example, I was assaulted quite badly while on duty and received GBH level injuries. In addition to my regular pension I receive an injury pension, or "award" which is tax free. Although my paper income is lower than when I was working my actual "take home" pay (I detest that term, but hey-ho) is higher because I dont pay tax on most of my income. That has a knock on benefit when applying for other stuff as my taxable income is low and injury/disability pension are excluded for most calculations. In the private sector that would have come down to an employers insurance, which could be very variable in outcome.
So lots of odd factors to consider, making the final decision a complex one.
Best of luck in (or if) your new career.