I collected the eboard a week ago and played tens of games using Chessnut Android application with Online Lichess account connected. The delay between recognizing opponent moves and showing them on Chessnut Pro is quite big, and the same recognize my move on eboard and showing it on Chessnut-Lichess - it takes time. If you don't want to lose on time you have to play longer timing game Rapid 15+10 or even longer.
Overall, over a week, there were few issues with not recognizing moves (leds start lightning on many squares), sometimes could be repaired by repeating moves on eboard, sometimes game has to be finished using mobile phone and after reset of eboard and/or application all worked fine again. This was acceptable and I would rate eboard between 4 and 5 (if it was faster and could be used on Blitz 5+3 games that would be 5). BUT... Yesterday (after a week of use) eboard was showing <10% of battery and I charged it fully (it was 2nd or 3rd time of charging). Today eboard is not recognizing castling (which before worked fine) and after castle (both 0-0 or 0-0-0) leds on squares involved in castling are lightning, the next moves are not recognized and it is not possible to use eboard. Restart of eboard does not help, the same restart of Android application. I tried few times, lost few games and had to finish them on mobile phones. I hope this will be solved as it is quite expensive appliance and it should be working properly not a week, but years.