The first one I guess. It all really depends on the physical dimensions though. I'd be happy with a similar form factor to the GPD XD since I don't really care about a keyboard. The main things I'd want for a windows gaming handheld is guaranteed x-input support so it's hassle free as is reasonably possible and hdmi output so I can work on a big screen when sorting out game settings, setting up emulators and other desktop things.
The only other important thing I can think of at the moment is that it can support as high a microsd as possible so since PC games tend to take up a lot of space.