I can't imagine getting around the Big Island without a car. It was perfect for going from one place to the other. I did some research on which rental models were best suited for touring around, and it really depended on the activities that I wanted to do. As, I previously mentioned in and earlier post, Mauna kea was at the top of my to-do list. It is recommended that you use a four-wheel drive car if you're climbing to the summit, however, many of the rental companies had specific roads that they didn't allow you to take their cars on especially in Hawaii. I wasn't sure I wanted to go to the summit, but I wanted the option. Also, the Waiapo Valley has a paved road that is open to the public. It is quite steep and requires you to have four-wheel drive. I recommend somewhat planning ahead to figure out exactly which sites you want to see and if you will need four-wheel drive.
I went with Thrifty care rental service, which I have always had good luck with and it earns points for the US Airways Dividend Miles. It is located next to the airport and had exceptional customer service. I chose their Ford Escape model, but to my surprise when I got there they only had a Jeep Liberty available. It was perfect for me, the only things better would have been the Wrangler. The Liberty allowed me to have four-wheel drive if I needed it, and it had a spacious trunk that I utilized almost everyday. I packed for everything because although I had an idea of where I was going, I didn't have a set itinerary. The gas was obviously more than it would have been for the compact car, which is a good option if you know your not going to need the four-wheel drive, but it was affordable. For the rental I paid $320.00 for 10 days not including gas.
Driving on some roads can be difficult at night. Saddle road at night was difficult. There were sharp turns and rolling hills that could be a bit of a challenge if you're not comfortable driving in the dark. It is the most efficient way of getting from one side of the island to the other without going the long way around. Also, it was my understanding through radio commercials and talking to some locals that drinking and driving is a bit of a problem on the big island. Driving with caution is advised.