I was using different private trackers but in the end dropped them and went back to public ones. One thing that private trackers may offer is the forum or the discussion board and plenty of user generated content. But in general there are many negative points:

• the drama: lots of users feel entitled and there is a very negative attitude towards newcomers
• less security: there was a time when an italian private tracker was caught and ended up giving the name and data of few active users. I don't buy that you have to use a legit email and no vpn.
• you have to pay for a seedbox and always track your ratio: I seed forever most stuff (4k+ torrents) but I don't want this to become a time sink