if you're joining at 40, you won't get to retire early with a pension like someone working there since their 20's, it is what it is but like you said, pension.
you pay union dues, so that gets deducted. check the fine print, if your pension has matching (eg $xx goes towards your pension, but you match it with your salary by % amount. This would mean whatever salary you think you're getting after deductions, take that away as well - it's still yours but goes towards pension).
you clock in and clock out and don't get pressure/stress with you (vs currently with your sales targets). you are also at the mercy of the union if you go on strike or whatever the masses decide.
overall i think it can be a good/safe move, and if you don't like what you're doing, i'm sure the org is large enough you can move around. if you want to & can move up, great - but with any org, you may need to build internal relationships more than say vs seniority (if it is non-union).
check how the probation works. some gov has a 6 month probation period meaning your benefits don't kick in, which may be an issue if your wife isn't full time and you have say dental or whatever for the kids. i had a friend working at a gov job with masking tape around his glasses waiting for his probation to end to get a new pair
also with gov there can be lots of procedures and red tape. some folks find it frustrating and say f-it and go back to private sectors. if you can understand it is what it is and work within it, then you'll be fine. gov isn't a place for cowboys.
when you have mortgage/kids a steady paycheck really helps you sleep at night.