I love visiting Iceland. My wife and family not so much. My wife thinks it is too cold, outlandishly expensive, and not exciting (too many waterfalls...LOL) and would not return unless I came up with a very good reason. The delicious herring choices for breakfast didn't help. I do know that my family would go back to spend a day or two at The Retreat at Blue Lagoon. My dad and I did Iceland and Greenland together on two separate occasions and had a wonderful time.
I have done Iceland on my own, with Travcoa now owned by TCS (highly recommended for quality), and had A&K put together an independent trip.
Independent on my own: Our family traveled with another family and rented two vans and stayed in only a couple of hotels in order to keep travel easy for all involved. There were 12 of us with one traveler only 2 years old. It was easy to plan and manage. I prefer doing travel on my own when possible. Because of the group we spent nights in Reykjavík and did day trips to various locations. The Iceland Parliament Hotel, a Curio Collection by Hilton, was a perfect centralized location for our group. I would stay there again for sure! I suggest considering doing Iceland on your own.
Travecoa (Now owned by TCS): This TCS experience is an almost exact replica of the trip my dad and I did numerous years ago. My dad liked having everything planned out and wanted to see multiple parts of Iceland. Our trip was more of a hybrid as my dad liked arriving and having meet and greets along with private transfers and private tours. If you like to keep planning and travel stress to a minimum and have the best services then I highly suggest using them.
Abercrombie & Kent: While I can find no similar itinerary anymore, of the 3, this Iceland and Greenland adventure was my favorite without a doubt. We visited remote areas of Iceland by plane and then flew to Greenland. The trip included incredible nature hikes, short day cruises, and memorable adventures. We visited: Narsarsuaq (Greenland), Qaqortoq (Greenland), and Narsaq (Greenland), Vestmannayjabaer (Iceland), and a few other unique destinations in Iceland.
In sum, the flights are cheap but the hotels, restaurants, car rentals, etc. can be a shock on the budget. When friends ask me if they should go to Iceland because of the cheap flights I always say to take a look at the other costs before committing.