Depends on what it is you want, but yeah it's a good choice if you want that kind of experience at the beginning of your leveling where the game feels fresh, Season of Mastery is the most suitable choice. The majority of vanilla servers (if not allof them, are no longer in existence. It's mostly just there for people to retain their characters as WOW TBC Gold an archive at this point. TBC is fine, however, it might be harder to join a guild now that you've made improvements. As soon as it's available, I plan to join SoM.
TBC realms. TBC realms were among the most well-liked, with Classic becoming less lively. I'm not sure if the coming Season of cheap WOW Classic TBC Gold Mastery will change this, but it will definitely pump some life into Classic.