I spent some time flying on the Big Island where Mauna Loa's main school is located at KOA. The Big Island offers a very unique environment. The tallest mountain in the world (Mauna Loa) measured from the ocean floor is located on the Big Island. If I remember correctly it's around 13,700 ft. above sea level. Mauna Kea is also over 13,500 ft. Puu Hualalai is another mountain located just above the airport (about a five minute flight) that's around 8,300 ft. These mountains are so big that they create micro climates depending on what side of the island you're on. The windward side is desert like and dry and the leeward side (Hilo) is tropical. They filmed the opening seen to the movie Jurassic Park here. It's a very unique and diverse place. There is no lack of high altitude flying available there for training purposes. You can circumnavigate the Big Island by helicopter in about four hours with a stop in Hilo. It's possible to meet the FAA minimums for x-country on the Big Island but not so on Oahu or Kauai. This is why the FAA came up with 61.111 (a) for pilots based on small islands. I know that some of the guys were doing inter-island flights from the Big Island to Maui to Oahu for fun as well. As far as tower work goes for a student - KOA is class D, so you will get plenty of work with that. Kahului (OGG) on Maui is class C and Honolulu (HNL) on Oahu is Bravo. There is also a lot of tour traffic on certain parts of the island to contend with as well. I really enjoyed flying there because the climate and terrain were so diverse. One minute your flying over active volcanoes checking out magma the next your landing in the jungle or on an ocean beach. The Big Island is definitely helicopter country with Blue Hawaiian, Paradise and Sunshine there to name a few. Many of the guys flying tours are pulling 6 to 8 hours worth of collective a day. The weather is good enough to fly year round. In general the atmosphere is laid back. The owner of Mauna Loa (Ben Fouts) is a great guy, you won't find many better. There have been a few people talking about flying in Hawaii so I just wanted to chime in and dispel a few myths. I don't think any one place is better to train than another. There are a lot of great schools out there. Some are better than others. Just do your research.