This script converts OpenMeta to OS X Mavericks tags.

convertOM2OSXTags.sh

#!/bin/bash
#
# This script converts OpenMeta to OS X Mavericks tags.
#
# http://code2k.net
#
# Copyright © 2013 CODE2K:LABS. All Rights Reserved.

mdfind "kMDItemOMUserTags == *" | while IFS= read -r file; do
  echo "$file"
  plistTags=$(mdls -plist - -name kMDItemOMUserTags "$file"|grep -v "kMDItemOMUserTags\|dict")
  xattr -w com.apple.metadata:_kMDItemUserTags "$plistTags" "$file"
done

Still works on High Sierra, thanks!