It’s an adventure. It’s a very stiff climb so don’t attempt it if you aren’t reasonably fit. The first 500m of the climb was a steepish hill walk. The last 450m was a climb. The total journey took us 2.5 hours to climb 950m.
I went with Magmatrek who were very efficient in their guidance regarding the clothing and equipment you will need. Our Guide was Adriano who set a comfortable pace for our party and was very knowledgable regarding the geology and general information about the volcano.
Only bad thing about the trip was the weather! The clouds came in halfway through the climb and in combination with the ash cloud you literally could not see anything. We heard some tremendous explosions of gas at intervals but could not see the craters or any plumes of lava.
I would strongly recommend that you take the night climb when the wind is generally lower so there should be less cloud. In addition check the weather forecast before you book to make sure it’s going to be a clear night. Otherwise it’s a good climb but it’s not volcano watching.
We also went out on our boat to watch the volcano from the water. It was clear that night and we saw some spectacular plumes, so clearly very weather dependent.