I did a quick quality comparison to my Avermedia 4k card just to see what I'm dealing with since no other reviews out there show it and I would honestly say that I am impressed with the results. Although it does not appear to be as clean and crisp as the avermedia when it came to quality it still is much better than I expected, especially for its price (rest of thoughts about quality in video). It is definitely a great and cheaper alternative to the El Gato HD60s (which I work with when live streaming).
Now on to what the headline states. As said it does appear to be a little finicky. After finding my camcorder to test it with a few days later, I plugged everything to where they need to be and for some reason my PC would not read the mirabox. I tested the pass through on my tv and that worked but my PC just did not recognize it. I tried unplugging and plugging over and over again and nothing worked. Eventually I restarted my PC with the mirabox still plugged in and upon rebooting the PC recognized it and I could finally pull it up in OBS and Xsplit.
I'm not sure what caused this or if this is the actual solution if it doesn't register right away but I'm hoping that this isn't a reoccurring problem. This is the reason for the 4 stars.
One more thing, the card is a sturdy aluminum box with little to no ventilation. So although durable, it is also susceptible to getting hot. Keep out of reach of children and other objects and try to give it as much space as possible.
As an alternative to the more expensive cards USB cards I definitely recommend, especially as a starting capture card for the new budding video game streamer/content creator.