High Sierra ".1" Released
Tony Still This release appears to fix many issues though my experience is that little change is visible (except a flock of new emoji). As a reminder, if your Mac's start-up drive is an SSD (not a mechanical or Fusion drive), it will be converted to the new APFS filing system; if it isn't, it won't. There is no choice about this.
The good news is that APFS seems to be behaving well, I have seen no chatter about problems and my machine has been fine (touch wood!). Time Machine continues to use the older HFS+ format.
APFS brings a new "snapshot" system that makes a record of the disk's state, allowing reversion to that state. If you are already running HS on APFS, a snapshot is made by the 10.13.1 installer before it makes any other changes so there is another way to recover should the update go horribly wrong (see Eclectic Light for more details).
This release is usable by those on the initial release of High Sierra, with or without the "Supplementary" update that followed it, both of which are called 10.13 (.0).