The Duo, launching Sept. 10 for a cool $1,400, isn’t exactly an ordinary device. It may or may not be a product worth buying for most people — that’s yet to be seen. What we can say, though, is that the Duo is a first-generation stab at a very different class of gadget. It’s intended for a very specific type of tech user. And approaching it with the standard review technique of comparing components and obsessing over specs is going to miss the bigger picture of what it’s all about.