Federal tax deduction on health insurance can be taken if you:
- Itemize your deduction.
- Costs over 7.5% of your income.
So, in your case, if you itemize your deductions, in the latter case you'd be able to deduct 5.5K of the health insurance costs.
In the former case however you "deduct" everything as you don't pay tax on the 10K at all.
So, basic math shows that with the $50K salary with $10K insurance paid entirely by the employer you'll end up with more net money in the end than with $60K salary with the $10K insurance paid by you.
In the first case you pay taxes on $50K, in the second case you pay taxes on $54.5K (with itemized deductions) or $60K (if you take the standard deduction), on the same $50K income.
Pub 502 for details.
Note, if you're paying for an employer provided plan directly from your salary, then you're paying pre-tax money in both cases, and then you'll pay taxes on $50K in both cases, so it is a wash. My calculations refer to the case where in the first case the employer provides the insurance, and in the second case you need to get your own insurance and pay for it separately, not through your pay-check.