Quick verdict: Worth it, with preparation.
We went to the Mauna Kea summit for sunrise, and the experience itself was awesome.
The biggest practical takeaway from our visit was simple: take the four-wheel-drive requirement seriously.
The experience
Seeing sunrise from Mauna Kea was memorable enough that I would recommend the experience to someone visiting the Big Island who is comfortable with the drive and prepared for the conditions.
What I would check before going
Before making the trip, verify current road conditions, vehicle requirements, weather, summit access and any closures. Conditions and access rules can change, so those details should always be checked close to the day of the trip.
Worth It Scout verdict
Worth it, with preparation. The sunrise was excellent. The important thing is making sure you have the correct vehicle and know what you are getting into.
My original takeaway
Went to the summit for sunrise. It was awesome. Definitely need 4 wheel drive.