It was tested with four HDMI 2.0 cables from two different manufacturers. My observations:

1. Up to 4K/30Hz there was no problem. From there, at 50 and 60Hz, there was an issue with the signal, with colored pixels flickering across the screen. It was more pronounced with certain cables, but the problem was evident with all of them, especially on a dark background.

2. It was slow to display the signal when connected to the computer, as well as when changing resolutions from lower to higher.

3. Occasionally, the signal would cut out.

4. The connector became quite hot after a short period of use.

I returned it and purchased a similar product from a different manufacturer, and all the issues were resolved.

As someone else mentioned, it does exactly what you buy it for. If your MiniDP output supports 4k 60Hz, and your HDMI input does the same, with this adapter and a High Speed HDMI cable, you are 100% sure that it will play 4k 60Hz. It has an Active converter with a quality chip, and that is the main reason why it works. I tried two others in lower price ranges and failed to achieve 60Hz, so I made the decision.

It was purchased to pass a 4k 60hz signal from the laptop to the Smart TV, as my laptop only supports 4k60 output through miniDP and not HDMI. After installation, I had to enable 60hz from the "Intel graphics settings", as well as the corresponding option for "full range scaling", and I was ready to go. Of course, the HDMI cable from the adapter to the TV must also be version 2.0 or newer.

The adapter worked flawlessly and is actually more compact in reality than it appears in the photo. It's a bit expensive but it's the only way to achieve 4k 60hz. Don't even bother trying adapters that are not active.