Its prolly unknown, theres barely any f2p game where any1 has reeached maxlevel xD j/k.
I dont know, really. I know that 2moons will feed you with grind for about 1 and a 1/2 year .. or is it 2.. and theres still like only 5-10 maxlevelers in that game (not sure at all, havent checked for weeks, but when I checked there was only 1 person maxlevel)
