See this forum was setup in 2010 by the bitcoin founder Satoshi and till then it has remained the most famous and knowledgeable open discussion forum to the users.You have been using this forum from seven months and what good reasons you yourself find to stay here rather then shifting to the other forums you have mentioned?

You can participate in healthy discussion and learn from high rank members about different topics and enhance your knowledge in the meantime and you can gain knowledge on all topics plus you have different local boards to have word in your own language.The other forums are full of spam posts while Bitcointalk has the most efficient and experience high rank members ready to help you in every doubt.

Now speaking of other forums you have mentioned then Bitcoingarden has it's interface copied from this forum and only slight color change is there but you see the most active members were 2131 on January 2018 so what else do you expect from them?

See their stats

But if you see Bitcointalk then there is huge active member userbase and hundreds of topics created on daily basis and have moderator also for spam handling as well other report handling.This is best place once you come to know about it.