A must ride for anyone that visits Maui. There will be many advertisements on a 38mile downhill trip but I would recommend riding up instead. The climb is VERY long but the joy when you reach the 10,023ft mark is amazing. Although I only made it to the ~9,000ft mark observatory(It was reaching 20F otherwise I'd continue) I would still have to say that it was one of my more challenging rides.
Downhill is absolutely amazing. I was easily in the 30+mph range for 30+ miles and the turns kept me on edge.
Try it and you won't be dissapointed.
PS: Whats up with the lack of a cycling scene in Maui
I joined a group ride of 12 and they claimed to be one of the biggest on the island