Our tour guide was great, watching the scenery change on the drive up Mauna Kea was awesome, the view at the top, as sun set, was incredible, and at the end of the tour when we stargazed, the tour guide really wanted to make sure everyone got to see something cool which was really nice. The only critique I'd add is that the pick up/drop off location for Hilo is not great if you're staying close to downtown and don't have a vehicle.