Son Doong cave is only accessible by tours with Oxalis. The cave is truly a wonder of the world and I highly recommend that anyone who is able should visit.
The ratings here are a combination of the cave itself and the tour group. Food was better in the cave than in the town we stayed in before we went on the tour. Friendly, professional, and hard working - this tour company does an amazing job of making the cave live up to its hype!