Rewired sets a very high standard to match when it comes to input handling in my opinion. Rewired supports is well known as the reviews of the product show. The number of controllers supported out of the box is yet to be matched on any platform. The biggest issue for me for the new Unity input system is what happens when it gets broken? For example a operating system vendor might just change how a usb driver works for game controllers (Windows 10 has done this a few times already in 2016). How long will I have to wait for a fix from Unity? I look at how well Unity supports it current input system as a indicator of what type of support I can expect for the new input system. As developers it is important to do an evaluation based on a vendors past and current level of support. Because at the end of the day if input is not working our customers do not care what input system we are using in our product. For me a well supported input system is what I need and I have that today with Rewired.