Kamado Grills are often made of a ceramic material and in the shape of a dome. They are heated with charcoal or wood which makes for excellent barbecuing.  They evolved out of clay cooking which has its roots in Japan and India with similarities to a Tandoori oven.

The strengths of the Kamado Grill include

• Even heating. There are few hotspots like traditional gas grills because the fire is seated lower in the grill which heats up the ceramic materials and then distributes the heat through the domed architecture of the cooker.  This combination creates the most evenly cooked meats I have seen.
  
• Wood, Charcoal and Gas. Kamado Grills are the most flexible type of grill when it comes to the types of wood, wood chips, charcoal or gas options. When time is short, you can heat some grills with a gas ad-on and add a few wood chips for flavor. When you have more time for grilling, you can place small wood logs which is great for doing a Santa Maria style barbecue over oak. The other nice thing about the gas option is it makes it easy to light the wood or charcoal. It beats newspaper or lighter fluid in my opinion.
• Extremely Low or High Temperature Grilling. Kamado barbecues are extremely flexible when it comes to controlling and cooking at varying temperatures. It's important to check the capabilities of each brand of Kamado, but cooker's specs say they can cook evenly at temperatures of 140 degrees for long slow cooking or as high as 900 degrees from what I've seen. I'm not sure if it ever makes sense to get your grill this hot since most searing only takes a few minutes at 700 degrees. It's also important to note that heating Kamado Grills quickly to high temperatures can cause the ceramic materials to crack.
• Custom Look. At least two makers of Kamado style grills allow for customization of the tile which gives a custom and unique look. I actually consider the grills in this class to be almost like outdoor furniture. They can be the show piece of the patio.

Negatives of Kamado Grills

• Kamado Grills are on the expensive end of grills. While Kamado Cookers are very versatile, with options, the price is usually well over $1000. Unless you barbecue a lot, this can be a high price tag. Too bad Costco doesn't sell Kamados.
• Weight. Kamado Grills, especially the ceramic ones covered in tile are extremely heavy. Close to 500 pounds. While they have wheels, they are difficult to move upstairs and the large grills take up a lot of space, although they look fantastic.
  

The real skill in learning to barbecue or grill with a Kamado is controlling the heat. Heat in the Kamado is controlled by a combination of the amount of fuel (wood, charcoal), air flow from the bottom of the grill called the draft door and how much heat and air is released from the top through the damper. It takes a little learning to control the airflow.  The more air that is exposed to the charcoal or wood, the hotter and faster it will burn.  You can use a thermometer to gauge the temperature and once it is at a desired heat, it takes very little tuning to maintain the tempature within a few degrees.

I asked the question, which Kamado BBQ should I buy, and got some good answers. Below is my own research.

The Komodo Kamado Grill. This is the highest end grill of all the Kamado style grills costing in the neighborhood of $3,000. All the reviews insist that it is the highest quality grill. It uses a different type of material for insulation called a two part refactory material. The two layers are designed to withstand very high temperatures, but one layer is designed to hold heat. The reports on this material is that it lasts a very long time and is much less prone to cracking and damage compared to other Kamado Grills. The Komodo Kamado comes in tiled and coated versions. The tiled Kamados wiegh nearly 500 pounds, but they look like works of art. It also has a gas starter option that is one of the few ad-on items for the Komodo. Like most premium products, it comes with very little additional choices, although I think a side-table option is coming soon. All in all, this is the top Kamado on the market. If price isn't an issue, I'd go with the Komodo Kamado grill.

The Big Green Egg or BGE as its fans call it. I think that the Big Green Egg is perhaps the best known ceramic grill. It's limited options in color (Green) isn't so much of an issue, but you'll need to get an aftermarket gas starter if you want convenience of lighting it up. The BGE has a loyal following and appears to be the most professionally run of all the Kamado BBQs. It has a professional website, although you can't buy new Big Green Eggs online, you'll have to go to a specialty barbecue store to find them. Or, you can look up dealers on their website. For a mass produced Kamado at a lower price, I think the Big Green Egg is a nice choice.

The Kamado Grill. This is the original Kamado grill and a bit of a sad story. I was very close to purchasing a Kamado Grill, but as I did additional research, I became very concerned. It appears that early on Kamado built a loyal following, but quality issues began to malign the product and customer satisfaction seems poor with many complaints about long delivery times, tile falling off, and replacement parts taking a long time as well. The company seems to have moved its manufacturing around as well. WikiPedia chastises the company with reports of Portland cement used in the ceramic materials of the cooker, although that seems like a long shot since its now made in Indonesia. My neighbor has the Kamado Grill and loves it, but he too has had issues getting replacement parts. To be fair to the company, it appears as if they are trying to improve their reputation. They answered the phone quickly when I called, and explained that many of the complaints are from people that didn't follow the break-in instructions. Still, I don't know of many products where there are dedicated forums purely for the purpose of complaining about the product. One other concern is that when I went to place my order, they only take check. This was the last straw for me in a series of red flags. I thought if I couldn't get the insurance provided by my credit card company then I shouldn't take the risk of buying the grill with all the complaints. Unfortunately, I have to recommend that you do serious research on the Kamado grill before purchasing.