TRex Arms did a really good video comparing them and highlighting the pros and cons of the Sionyx.
https://www.youtube.com/watch?v=e3SN-ZSG7ls
Seems he agrees with general consensus where while it's okay, the tech just isn't there to be comparable to analogue night vision yet. Probably in the near future when processing power and sensor capabilities increase, digital night vision may start getting more competitive.