Vote http://www.gamesas.com/topic/1440825-b2p-subscriiption-f2p/.
Another http://www.gamesas.com/topic/1440529-monthly-fee/.
Personally I'm not in favour of F2P or B2P. Well I am

Why would you want people to grind for a month and allow players to buy it for cash? It takes away any sense of accomplishment or prestige.
Furthermore I'd say that if a company's income comes directly from the number of subscribers, it would push developers into making more and better content and keep the game enjoyable. Instead of inventing all kinds of stuff to redirect people to the cash shop.
You what would you choose?