Tribunal does it work?

there isn't one? I'm pretty sure they are overhauling it at the moment.

From what Riot says it was pretty accurate, although they felt the Tribunal was often too lenient (so much for "Tribunal users spam punish").

But Riot has taken it down to rebuild it because while it was accurate in punishing people who deserved it, they're not okay with just banning toxic players. They want to reform toxic players and encourage positive behavior. I'm not sure how they're planning on doing that, but I believe that's what they're working on. They also want to deploy the new Tribunal to all regions as the old one was limited to only a few regions.

No ETA on when the new Tribunal will launch but if I had to guess I'd say not until season 5. Riot likes to take their time with things.

It's better than nothing, but worse than it could be. Right now it's not in session (it was having issues so they're essentially rebuilding it from scratch); when it's back, it'll hopefully work better.