Due its compatibility and stability I would prefer to use VirtualHere (optimized / licensed) on Raspberry Pi 4 instead using Silex DS-600.
Software on Silex DS-600 is sometimes picky and not quite stable.
However, I made a speed comparison with following results:
Silex DS-600 USB-Server / Transcend 128 GB USB3 Stick: stable 120 MByte / Sec. (1,5 GByte file)
VirtualHere (optimized version / licensed) on Raspberry Pi 4 (USB3-Port) / Transcend 128 GB USB3 Stick: 35-40 MByte / Sec. (1,5 GByte file)
I am a bit surprised but I think, limitation is on side of Raspberry Pi 4. On the other hand, Silex DS-600 also uses a small linux system but seems at all much more powerfull regarding speed.
Is there a way to optimize something?