Trying to mount an NTFS partition in Linux that was left hibernated by Windows can create a real mess.
No, it can not. Read-only mount is allowed but read-write mount is refused unless the 'remove_hiberfile' mount option is specified.
Microsoft designed hibernation in mind for the case when the hibernation file must be removed and they ensure that the filesystem remains consistent. They didn't do it for Linux interoperability but for themself when they are not able too boot otherwise.
NTFS on Linux is slow.
Yes. And sadly FAT and ext3 is even slower. There can be many explanations for slowness, some are apparently explained on http://www.ntfs-3g.org/support.html#slow
Have you EVER seen a Mac in production running on top of a NTFS read-write RAID?
Never. Only on Linux using WUBI.
Btw, does Mac indeed support RAID already?
Disc space -- the final frontier!