I'm also using Tixati and have been for ages, though I've only been on Metal-Tracker for a short while. Tixati seems to download very well but either I'm into unpopular music and no one is trying to download or Tixati isn't seeding properly. I set my torrents to seed to upload ratio of 2.0 but it isn't working with torrents from here. Any other tracker works just fine. If I knew anything about how torrents and trackers worked under the hood I'd offer to help but I'm just a humble pleb.