Free coverage is a no-brainer. Some employers (including mine) will let you buy additional coverage as part of the group. This gets trickier, as the group purchase option may save you a couple bucks if your health is poor. At my company there are age buckets and it gets less marketable as you get past 40.
But there is a bigger reason not to use this as your sole source of insurance than price, if you have an insurance need. It is that you may not always work for this employer. What happens if you get canned on Monday, go home to tell your wife, the mother of newborn triplets, then get killed in a hit and run on the way to the unemployment office on Tuesday? Similar, what if you work for your employer for a good number of years, get married, start a family (have an insurance need), and then at some point you discover a medical issue that will eventually kill you, but will certainly now kill your ability to acquire life insurance. Now you may be trapped in a possibly no-good job, with perhaps a terminal illness, or a risk profile that isn't terminal but is uninsurable.
Not the question of the thread but thought it useful to raise these issues if it lives on in search. Cliff notes - when you need insurance, buy some level term (20 - 30 years) independent of your job.