If you are going to see glowworms, you have to go with glowing Adventures! No one else signed up for our time, so we got a personal 2 people tour. Not rushed, had all the time on the world. We got great explanations and our tour guide even took pictures of us, including a long exposure one that captured the beauty of the glowworms.
We were provided with all the clothing/boots we needed, and got cookies and coffee afterwards. It's on their private farm, so the caves were in pristine condition, non-commercialized. Some areas got pretty tight, and required some scrambling, but your tour guide will guide you into the appropriate areas of the cave.
Also inevitable to get water in the boots, but felt great and the clothing they supplied kept us at a perfect temperature.
All in all one of the best tours we have ever been on!
We were also fortunate to come in the spring when it wasn't too busy and get a great $100 dealing bookme.co.nz 2 days before!