I have had the receiver for 2 days now.
I got it for viewing nationwide channels at our country house, as we are in a blind spot when it comes to terrestrial reception.
My first impressions are very positive.
First of all, it is extremely small! Very convenient for transportation and placement anywhere.
It also has a nice minimalist appearance and seems to be of high quality construction.
Now, onto the important stuff. Although it is an FTA receiver, it has many hidden features...
You just need to install the unofficial Firmware.
Download and extract the latest Firmware to an empty USB stick from here
http://www.sat-soft.net/index.php/158-picco-s2-pro/159-software
Insert the USB into the receiver and make sure to upgrade not only the Software but also the Bootloader. Instructions can be found in the text file of the compressed archive that contains the Firmware.

As for the opening of Greek channels (ERT & DIGEA), it happens automatically (without any other action), if you have previously installed the above Firmware. And if anything changes in the future, besides Firmware updates, there is also the possibility to edit the BISS keys by going to: Menu -> Card System -> Key Editor -> BISS and editing the keys that may have changed, using the receiver's remote control.

From there on, depending on your knowledge, you can take advantage of other, more advanced capabilities of the receiver... Especially if there is an internet connection.
If you are not interested in the internet part and only want the receiver for Greek channels (ERT/DIGEA), because you don't have access to terrestrial reception, you can easily choose the basic model (EDITION PROTON S2), which can also have internet with the corresponding EDISION WiFi module if needed at some point...

OBSERVATIONS (I won't say negatives, because I'm not sure if they are due to the receiver or the small 60cm dish I have)

Sometimes, there is a delay in the sound (more than normal) compared to the image. It's not something that happens constantly but it can occur.
And it doesn't occur on a specific channel, whether it's SD or HD.
The same channel, when I select it again, doesn't have a delay.

There are also 2 channels that haven't appeared in the list of Hellas Sat 3 channels.
ERT 2 HD and ERT 3 HD. I can receive ERT 2 and ERT 3 as SD but not the corresponding HD channels.
However, I don't think it's the receiver's fault for this.

To conclude, I think it is a decent choice for its price, with advanced capabilities for knowledgeable users or those who want to explore it.
You can find a detailed Greek manual (for the official Firmware) here:
https://www.edision.gr/index.php?ACTION=_download_file&fp=39587

If anything comes up, I will come back...