Volcano is highly active right now so there is high chance for a unique experience I would vote BI given the volcano activity.The Big Islad is my favorite due to volcanoes, black sand beaches, tropical gardens, cattle ranches, astronomical observatories, and snow-capped peaks, all on one island. There are not a lot of sandy beaches but the ones they have are beautiful. My parents bought into Kona Coast, now a Wyndham, so we’ve always stayed there, and as a result I don’t know about other resorts.
But in reality you can go to any island they will all offer very similar experiences even for first timers. You can also take day trips and island hop, do a activity and be back within hours. For instance on Kauai you could do the helicopter tour one of the most famous to do activities, for Oahu you could go to Waikiki and hike Diamondhead.
Best Hilton of course is Waikiola, We stayed at Bay Club and liked it. Although it's further away from the action and a bit of a drive, I would if preferred to stay near Captain Cook, nice resorts there also.