I was looking at Lowes. They had both the Highland, and the Longhorn sitting next to each other. There is a bit less than a foot difference from what I see. The metal is identical. I went with the Highland...mainly because I do not have a truck to haul the Longhorn, and I hate asking friends for favors. The Highland demo model at Walmart was the best of the 4 I looked at in the fit and finish department. I took off the chimney and legs and it fit in the back seat of my BMW 540i! The garden center lady was sure I had lost my mind hauling a smoker in my BMW, but, like I told her,...you work with what you have!!
With the 3 you listed, I don't think you could go wrong with the OK Joe. It is so much heavier gauge steel than the others. With a few easy inexpensive mods, It will be as good as some much spendier units!