It USED TO BE the cheapest around. That was back when they only allowed Officers to belong. 10 or 15 years ago, they opened it up to the enlisted ranks, and it became an average company. I was an officer with very low rates, and they've been climbing ever since the enlisted joined the ranks.
As with most things, shop around.
Edit: I should add...they are very, very good at customer service. I've been a member for 22 years and have no complaints. The people at the end of their 800 number are awesome, nice, and very helpful.
Retired Air Force, half enlisted, half officer.