Having my own local print magazine I can tell you it's tough to get one off the ground. Can't imagine doing a national one. We broke even the first month and should make a small profit this month. I'm working with my family on this and they don't have a clue about the internet so it's been an adventure. I'm trying to apply some of the internet marketing strategies I know to the magazine and they just don't get it. Gotta love family.
As for subscription based magazines, they are a dying breed. TV Guide sends me 6 copies each month because I used to have a retail business. These are "waiting room" copies but sending me 6 of them makes their distribution rate look better to advertisers. The internet has put a huge dent in the print industry but the strong will survive. That's why we went with the free model entirely supported by advertising. I don't have the kind of cash to compete with RB, Playboy, etc. So far it's working well but time will tell if it works in the long run.