We found an excellent bus company which we used for most of our stay in Iceland. They are a very dependable company catering for tourists. They are very prompt on pick-up and drop-off and responded quickly to all our email inquiries.
All their buses are spotlessly clean and have free Wi-Fi. The drivers help you with your luggage when they pick you up at the airport or at the hotel. They have knowledgeable and entertaining tour guides. For the Golden Circle, our guide was entertaining and very helpful. For the northern lights, our guide was particularly determined that we should see the lights, and we did.
Cancellations of tours (due to bad weather) are notified by email early enough for you to re-schedule them and make plans for your other tours. We will certainly recommend our friends to use this company in Iceland, especially during the winter, as the weather and road conditions are highly unpredictable.