today for a used shield portable you're looking at less than 200$ in a sale, unless you sell it on the street to someone with little or no sense. Thats entirely depending on the condition as well. They're going for as little as 79$ working with a few scratches. I would keep it unless you know someone who will definitely buy it at the price you're looking to get for it. It will always be able to emulate what it emulates, and barring a major change in gamestreaming, should always have access to remote stream PC, xbox one, and ps4 games. Plus you have moonlight if nvidia decides to kill the portables support from their drivers. Until the battery stops holding a charge, it probably has more value in your hands than on ebay. As for the xd, i wouldn't buy it, I would wait for the GPD Win, the PGS (if it makes an actual appearance) or the XD2. While you have the shield portable, there's really no reason to spend more money for an inferior handheld. If size is a huge or the only factor, then you could probably unload the shield and buy the XD, with a low enough net expenditure to make it palatable. I know the feeling of wanting something new, so i dont want to downplay those feelings in any way, but in the short term, you're just going to be putting yourself in this same position again when the proposed better handhelds launch in a few months if you buy now.