From GENERIC:

file-system     NTFS            # Windows/NT file system (experimental)

How experimental is experimental?

I just had a go:

# /dev/rwd0d:
type: unknown
disk: QUANTUM FIREBALL
label: fictitious
...
8 partitions:
#        size   offset     fstype   [fsize bsize   cpg]
  d:  8418816        0     unused        0     0         # (Cyl.    0 - 14847)
  e:  4192902       63      MSDOS                        # (Cyl.    0*- 7394)
  f:  4209030  4192965       NTFS                        # (Cyl. 7395 - 14818*)
# mount -t ntfs /dev/wd0f /mnt
ntfs_readntvattr_plain: POSSIBLE RUN ERROR
ntfs_readattr_plain: ntfs_readntvattr_plain failed: o: 0, s: 131072
ntfs_readattr_plain: attrib: 0 - 31
mount_ntfs: /dev/wd0f on /mnt: Argument list too long

and yet on

# /dev/rwd0d:
type: unknown
disk: QUANTUM FIREBALL
label: fictitious
...
8 partitions:
#        size   offset     fstype   [fsize bsize   cpg]
  d:  8418816        0     unused        0     0         # (Cyl.    0 - 14847)
  e:  4192902       63       NTFS                        # (Cyl.    0*- 7394)
  f:   208845  4192965      MSDOS                        # (Cyl. 7395 - 7763*)

mount -t ntfs /dev/wd0e /mnt
worked fine! (Somehow I managed to mount (-t ffs) /dev/fd0a /mnt on top of
it - I'm not sure that should be allowed..)

Cheers,

Patrick