Comfort // To be completely honest, encasing your lower legs in rubber is not the most comfortable of options. The Tours do have a distinct advantage in that they don't weigh 12 pounds each. The Originals are much thicker rubber, which makes them, in my opinion, much more uncomfortable. As long as I don't get too hot, I can wear the Tours all day, which I could never do with the Originals. Honestly, my legs would get tired of lifting the giant boots up by about noon. Tours for the win.
Look // The big downside to the thinner rubber of the Tours is that they sort of wrinkle on my legs. They don't fall down or anything, but they are certainly more pliable. Again, I find this a fair compromise for the comfort, but they definitely can look a little more sloppy. Also, the Tours come in a much more limited array of colors, so if you're really dying for pink boots, the Tours aren't for you. I found both to look the same in terms of tightness on my leg. I was concerned about getting the Tours on, but found the shaft plenty wide.
Longevity // I owned Originals for 3 years without any problem, even with frequent use and non-optimal care. The Tours, on the other hand, died a pretty dramatic death after only 8 months. Luckily, Zappos was great about exchanging them for a new pair. I'm hoping that those specific boots were the issue, not Tours in general, but if this pair develops holes along the edges, as the last one did, I'll absolutely switch back to Originals.
Specs // The Originals have a shaft height of 16 inches, while the Tours are 1/2 an inch shorter. The Tours also have an inch wider calf circumference (16 vs 15 inches). The Originals weigh 2 pounds, 2 ounces and the Tours are 1 pound, 8 ounces, but I promise, you can feel that difference.
You can buy Originals here and Tours here