Population: Low (really low) - almost non existent compared to New Frontier f2p.
Fun: Yeah, with the right guilds you can have fun, however a lot of content is cut out, cause of the lack of people.
Worth Subscribing: Depends what you expect from game. PvP - not worth; PvE - maybe worth;
You still can experience Allods without the need to buy something though, but if this is worth enough to let the lack of population (and thereforce activites) doesn't disturb your fun.... you need to decide for yourself.