What are torrents - an instruction manual

Yes, it's an ordinary service, choose any one to your liking. A torrent client is a program installed on the user's computer that does all the work of downloading and distributing files. 

It all depends not on the service, but on the content you're looking for. I use the pirate bay and even in spite of bans and blocking I will still use it. Just because there is no such a huge amount of content anywhere else. Moreover, to gain access it is enough to use WebPN and know the mirror sites. But the choice is always up to you.