After installing it and 4 or 5 reboots, virtual USB disappeared and on the next reboot most apps had been erased from smarthub which took a long time to reinstall them.
Since that it seems to be more stable.
Pros:
- libSkype.so file is no longer automatically replaced by original or erased, so SamyGO still works after many reboots for now
- Previous version was frequently awakening my NAS HDD over LAN/DLNA even if not in use, doesn't seem to do it anymore
Cons:
- Still needed to initially replace files in /Skype dir, else no virtual USB is shown
- Virtual USB disappears when a physical USB device is plugged/unplugged until next reboot
Maybe I need a little more time to confirm all that, so I'm going to install the "V3"(?) which is 5 bytes larger!?

edit: just a question, when I replace a SamyGO version by a newer one by ftp, do I need to launch it once again in smarthub or just reboot, and is it preferable to uninstall it before?