When the retro receivers are plugged into the PC, they are always seen as being on, no matter whether your controller is currently powered on or not. What this means is that you cannot reorder your Xinput controllers by turning them on and off. The receivers must be physically unplugged from the usb connections. That basically breaks PC functionality for me. I don't want to have to unplug a retro receiver to use a different xinput controller when I'm playing a steam game, for example.
The Wireless xinput dongle I got from Microsoft supports 4 Xbox controllers and you can change the order at any time by simply turning the controllers off and then on again in the desired order. I also don't want to have to use extra drivers or software to make a fixed order for these retro receivers. I guess it was too much to ask that 8bitdo would design their products with optimal flexibility for PC usage, since that seems to be an afterthought anyway. I suppose that I could ask their support staff if they could possibly update the firmware, but for now I've gone back to using my Microsoft connector and Mayflash PS3 controller connector, both of which have been excellent.
I went ahead and preordered one of the new Genesis / Mega Drive retro receivers through Amazon.
I also ordered a Sega Teamplayer, Sega's multitap, new in box from Amazon Prime for $20. Even though they had a picture of the box and listed it as new, I really didn't expect it to be shrinkwrapped and have all the documentation, stickers, etc.
After smelling the 1994 air, I tested it out and found that it works, but its usage is incredibly convoluted. Rather than being a simple 2p-4p or 5p binary switch like the NES and SNES multitaps, you have a 6 position switch labeled Extra, A, B, C, D, and Multi. It also has two short wires instead of one, labelled as Controller 1 and Controller 2. The crazy thing is that you can't plug both wires in when you have a game that's compatible with the Teamplayer. You only plug both wires in if it's a multiplayer game that doesn't have teamplayer compatibility. And then you use the extra setting instead of multi. You use multi mode when you have a teamplayer compatible game, but you plug the controller 1 wire into port 1 if you have up to four players and leave the other wire hanging, but you have to move the same wire over to port 2 if you have up to 5 players and then plug player 1's controller into port 1. The instructions don't say, but I'm assuming that ABCD switches are for choosing what controller to play as 1st player in single player only games. That's just a guess, though (I'll look it up eventually).
Between this and the 32X released that year, just further proof that, by 1994, Sega had completely lost their minds.
I'll test the retro receiver with the Teamplayer when I get the receiver, hopefully later this month.
*Edit* I looked it up. Apparently, EA is the reason for the complexity, as they made their own multitap adapter called the 4 Way Play, which sounds sexual, and refused to support Sega's peripheral (which initially was more simple and didn't have twin wires to connect to the console). I was also correct about the ABCD switch being for choosing which controller would be used as 1st player, so that you could have other controllers or peripherals, such as the mega mouse, plugged in and switch between them on a per game basis, although that still doesn't seem all that practical.
*Sigh* This will all be worth it if I can get a gang together to play some NHL '94.