My wife and I did not take a helicopter tour on our visit in 2003 and swore we'd take one next time. Sixteen years later, we made it back on a cruise. Looking at cruise line offerings, we found them marked way up. We did the math and found Mauna Loa did a longer, comprehensive flight and was just a bit more expensive, but we'd have the helicopter to ourselves.
Booking and payment were straightforward. My wife over-prepares for things and they were responsive when we called to confirm.
The taxi ride was about 10 minutes from the Kailua waterfront. There were no issues finding their buildings.
Our pilot/guide went over safety procedures and showed us on a map where we'd be going. He asked if we had anything specific we wanted to see and besides the volcanoes (which were already on the itinerary) we left it to him. He was personable, professional, and laid-back in the island style. He was also a native and life-long resident of Hawai'i, so he knew the island. His enthusiasm was actually palpable; he said the weather was great and he was excited to fly on such a great day.
I was slightly hesitant about the equipment - a Robinson R44, which I'd say is like a Corolla, compared to the flashy Cadillacs flown by other outfits. However, it did the job just fine and any reservations I had were forgotten once we left the ground. The aircraft gave us plenty of room; I'm 6'5" and found the front seat roomy enough for my legs. My wife is 5'9" and said she had knee room in the back.
Our flight went "over the Saddle" between Mauna Loa and Mauna Kea, over Hawaii Volcanoes NP and its assorted craters (no lava to be seen this day), to the south of Hilo, up the NE coast to the Kohala Coast, up one of the massive valleys to see amazing waterfalls, then around the west end of the island, and back down the Waikoloa coast to the airport. A request to fly back over Kilauea so we could both look down I to the crater was met with quick agreement.
Hands-down, this tour was the highlight of our visit to Hawaii. If you're on the fence about booking, let me assure you you'll be satisfied. Chartering a helicopter is not cheap, but if you can afford it, I doubt you'd be disappointed. Don't let the small size of the outfit put you off. They're not as widely-known, their equipment isn't as flashy as Blue Hawaiian, et al, but the benefit is a personalized experience.
I would not hesitate to recommend Mauna Loa Helicopters to anyone.