It would be really nice is there was a modern file system that "just worked" regardless of device. I'm tired of having exFAT/FAT being the only filesystem I can reliably use on multiple different OS-es painlessly, and even then I can't use it for all the functions of those OS-es (No time machine). Hopefully this will be open enough to enable that, though who knows how it will shake out.
Getting UDF to work with rewritable media, like usb sticks, is an unholy pain in the arse. It involves trying to remember an arcane combination of versions and feature flags to get the universal format to actually be universal. I managed it once, but after that, realized that the network was fast enough for most of what I needed and I tend to not have the four gig files that cause problems with FAT filesystems.
From what I understand, UDF is primarily targeted at one-time-recordable media. (It's used in DVDs, for example.) It's unclear how well it works for primary storage, but I suspect it's clumsy at best.
