Aloha from the Big Island all.
Nice! I've been to Oahu and Maui which were both fantastic. But I hear the Big Island is amazing. Are you going to go check out that lava flow in Pahoa?
Likely we will. We saw the flow two years ago when it was going into the ocean so this might be a little less visually exciting but still cool. We were on Maui last week.
The Big Island is probably our favourite (haven't been to Kauai yet) because it's so diverse and there's so much to do. The only problem lies in the name - it is very big. Where you can drive around the other islands and never really be that far away from anything here it's heck of a drive to most places. We're currently 2 hours one way from Pahoa largely because the beaches and weather are far better on this part of the island (Waikoloa in the south Kohala district). So if we go see the lava flow we're looking at a really long day but it would be worthwhile.