Well, over time, on average, of course your premiums will exceed the amount you collect in claims; this is the whole reason insurance companies are in business, of course. So it comes down to a few factors:

• How decent is the insurance company’s network? The “DMO” offered by my employer has REALLY steep discounts, but in the mid-sized city I live in, there are precisely TWO offices that participate, and in my one-year experience with that plan, they are both revolving doors for freshly-graduated dentists with no patient base that don’t yet have the money to buy into (or start) a practice. (You get a bad feeling when you call for a new-patient appointment and the receptionist asks you if tomorrow is fine, and offers you a half-dozen different time-slots.)
• If the network dentists are any good, how steep is the discount vs. self-pay? (Not to mention you can often sign up for a free/cheap “discount card” that gets you “Network” rates, but without any actual insurance coverage.)
• And lastly, you need to ask the same question you must ask for ANY form of insurance: “Is the premium worth insulating myself from the risks the insurance will protect me from?” My employer’s non-DMO “Basic” plan has a max annual payout of only $750. I could cover that entire $750 out-of-pocket without even blinking, making that plan utterly useless; it’s like taking out phone insurance on a flip-phone…