Aloha vmonk. In my opinion the vog issue is sensationalized in the press. The normal wind pattern on the Big Island blows most of the vog over the southern/southwestern part of the island, which is where most of the problems are. Here is a link to the air quality index from the National Park Service. http://www.nature.nps.gov/air/webcam.../havoalert.cfm

The majority of the island is not affected much by the vog, unless the wind pattern changes for a day or two. Hilo, Kohala, Hamakua are beautiful and mostly vog free. Kona mostly has a haze that lays just off the shore, obscuring the long view some.

The ocean entry site is in the Puna District and the vog is usually blown away from there. It's an awesome, not to be missed sight, along with Volcanos National Park.

Don't hesitate to visit the Big Island. My favorite places are Akaka Falls, Hapuna Beach, Volcanos National Park, the City of Refuge and for me, the Maku'u Market in the Puna District on Sunday mornings is my favorite place for local color and food.
Places to eat (I'm pretty casual): Kona: Big Island Grill, Jackie Rey's - - Hilo: Cafe Pesto,Puka Puka Kitchen, Ocean Sushi Deli - - Kohala: Merriman's Cafe and the fish tacos at the lunch shop at Hapuna Beach -- Volcano: Keawe Kitchen. Hope you have a great time.

We stayed at Hapuna Beach and loved it; our favorite sights were Akaka Falls - gorgeous, and Volcanoes National Park.