Any product well developed ends up good and functional. What makes it exceptional is the support. The support from this vendor is amazing. Was surprised at the response by vendor and his team, first by email and then by telephonic discussions. Area to improve : more detailed documentation. I tried to check the board functionality without connecting the board to the PI. I expected 3.3v volt at the GPIO when the input of 24V is given. That was my idea but latter was told that the 3.3v should be supplied by the pi. Sounds right and I missed it. Overall good product with exceptional support.
Very happy with the purchase. The board worked with an USB cable plugged in. Haven't tried the sample software they provide, instead I flushed the board with my custom firmware and everything worked as expected. They do provide a git hub repository with a software as well as some documentation, which I was expecting to find that on their website but couldn't access product description. Sent a quick email on a weekend and got a prompt answer (very impressed). Headers pin-out on the board are documented and you can easily work out from headers where are things connected, although wished they provide a full circuit diagram.
I'm using this board to power a NodeMCU which transmits temperature data from my garden to my home automation server. As I wanted to avoid using battery power, I was looking for a supply that can be hooked up directly to mains. I first bought just the transformer component separately but then realized that you need additional circuitry to protect everything. Instead of designing all that by myself, I bought this supply module instead. Shipping time was as indicated. The product came well packaged and has worked flawlessly for the few days that I tested it (freezing temperature outside).
I got one of the wifi dimmer boards for my circulation fan and it works nicely, now I wonder if I can use one for controlling my heated blanket to give me a better level of control. Another idea that I've got is to rewire my fan heater to allow the dimmer to control the heating part to allow more flexibility with the produced heat but without slowing the fan down. Had to write my software for it to meet my needs but other than that, the hardware is what I needed as it's something I'd not be able to build myself.
I bought the second time. For the documentation I gave only 4 stars because I didn't find all the Software for the board. But this might be my fault. Don't worry about that. The board is working quit well for my needs.