I've toured with over five different companies in Iceland, and I have to say Discover Iceland is one of the best.
I had already been to the Golden Circle on a previous trip, yet on a second visit to Iceland I decided to book the "Spicy Golden Circle" tour with Discover, hoping it would live true to it's promise to take you to some more off the beaten path stops. It truly did! In addition to Geyser, Gulfoss, and Thingvellir National Park (the "typical" Golden Circle sights), you get to see a black sand beach, do a short hike/walk to a stream with beautiful mountain scenery, and admire a glacier river. I also liked sampling the dried fish and malt - a nice touch & way to get a glimpse of Icelandic culture.
Aside from the route, the driver/guide, Orri, was wonderful - very personable! He planned the order of the stops in accordance with weather and times to best avoid the crowds. He urged everyone to take their time at each stop, and had just the right of information without droning on the entire trip (as some tour guides do). The tour felt personal with just 8 people including myself on a nice minibus.
The combination of lovely guide, off-the-beaten path sites, and small tour size made Discover Iceland's Spicy Golden Circle tour an excellent value for the money and a great way to spend my 1 full day in the country. I would not hesitate to recommend them or take another tour with them on a future trip.