Hello, thanks for this mixed feedback, always useful.
About the beep sound at startup, we initially implement this to inform the user of the booting process, but we are working hard to reduce this startup time to a handfull of seconds: it will not be needed in the next major software release.
Meantime in the next firmware, the boot sound (different from the beep) is be user customisable: you can either put the original "dung" or a game related audio file.
If you have any other remarks, I will be pleased to answer them, as Beelzeboob pointed, there is a lot on this thread:
https://pinside.com/pinball/forum/topic/pinsound-card-reviews-anyone
And it's probably better to continue on this to maintain a single entry for further reference.