It is a question of the extent of the dropout problem though. All USB solutions suffer from the issue to some extent (and that includes using a serial logger with a serial-to-USB adapter - I’ve encountered at least a couple of verified instances where this has happened with a serial logger, though fortunately both cured by attention to the leads, ferrite cores, sources of RFI etc). USBX does sometimes perform acceptably where the standard VCP driver fails, so it is definitely a useful tool in this context.
I know that Davis did look at other USB chipsets, such as those used in some of the serial-to-USB adapters, but although some performed somewhat better than the SiLabs one it wasn’t by enough of a margin to make it worth switching the production process. But ultimately, if you have an environment where there’s a significant amount of RFI around, then no solution connecting via a USB port is guaranteed successful - USB just does seem inherently more sensitive to RFI than straight RS232 when used continuously 24/7. Fortunately, a better understanding of the role of RFI in causing the problem, more recent drivers etc have reduced the incidence of the problem considerably - just as well really since very few serial loggers are purchased nowadays - but obviously a few unlucky users still do see the dropouts.