Vizio laptops look good on paper, but none are available yet so we can't recommend a product that's only been announced.
As for the rest of your suggestions, lists are subjective but rest assured we HAVE done our homework. We can't include everything either, so we had the draw a line where we thought we'd be highlighting a majority of the best laptops currently on the market. And no, order doesn't count, we listed the systems in random order on each of the sections so we don't favor a brand over another.
About the gaming laptops, Alienware pricing is competitive. But more important than that, Clevo IS being featured in the form of the Origin EON 17S which is based on a Clevo barebones.
Edit: Vizio PCs are just starting to become available now. Even Vizio site says "coming soon", but Amazon has them on stock. We will have to wait for the actual reviews, including our own to recommend them.