After initially just getting an OTG USB hub, which worked fine, I realized I wanted a cleaner setup and to have more than three "controller" ports, since one was taken up by a keyboard. So I got this and I haven't looked back. It's clean and works like a charm.
The only thing that was a little annoying was trying to connect the MiSTer and the USB board. The connector is kind of a Z shape where you need to plug it in to the MiSter board horizontally but it plugs into the USB board vertically. This is tricky since you're also constrained on board movement by the pegs to attach the two together. I was worried I was going to damage it while trying to put them together. And secondly, the boards are so close that you can't get your fingers in to push the connecter down on the USB board, so I had to use some pliers to grab it and force it down. Again, scary.
BUT after getting it together, it works great and I love it.