Everything depends on the person. For example the same 2 people can make exactly the same, but live in 2 different states.
And with state income tax is varying from 10% all the way down to 0%, this choice of locale can make a big difference
So even in the same state, two different employers paying the same gross salary could mean very different net salaries. Unfortunately, it's also a big pain in my experience to get companies to disclose this information before hiring.
If I had one wish it would be to decouple healthcare from employment. No one should have a nightmare scenario where they get fired on Wednesday and next week can't afford their wife's heart medicine.