I'm offerred Health Insurance at my job, but in doing online searches for private health insurance if I were, say, self employed, I'm finding that the premiums are sometimes cheaper than what I'm currently paying at my job for health insurance. How do I compare these insurance policies to be sure I'm getting the best deal?

Is it equal coverage, What is the deductable, of course at work your pre-existing conditions are normally covered under work insurance. Also at work insurance you can't be cancelled if you use it too much, and can not be individually picked out for price increases

You have to look at first what is the max they will pay, some policies will pay a max of lets say 9 million , others have a max of 50,000.
So you have to look at every item.