The pros are for the company as they have a set cost and don't have to worry about premium increases. If I were you I would research the cost of a policy that meets your needs. The total cost can be upwards of $1100 per month for a family with decent copays and deductables. I guess it all depends on how much they are willing to pay you to purchase your own policy. Chances are it will be a small amount that will allow you to purchase a very basic plan.
I would also find out if the amount of $ they are providing will be taxed. My guess is that it will. Kinda like a car allowance company pay $550 and you only net $300. On the bright side, you should be able to write off your medical premium come tax time.
Look at the opportunity as a whole, if you have the chance of making big commissions then this may be worth it. As you know, if sales in your territory drop so will your overall income while your health insurance premiums continue to rise.