I haven't gotten that much use out of it, because I rarely ask him questions (and sometimes when I do, his answer is a bit perfunctory for my tastes). I do subscribe to his supplement shipment, and get a discount on that for being a member. And seeing how much a doctor's appointment costs (even if insurance covers most of it), a few questions a year might be worth the yearly cost.
I guess you have to weigh what features you would use against the cost, and see if it's worth it for you.
HTH!