I just gave it a pretty good workout in 0.9.5 on Kubuntu 16.10 and it works great. I was even able to replace the config.xml and epub.css with my own production versions with no trouble.
This makes it essentially as easy for me to go from LibreOffice to Sigil as it would be to use the LO writer2xhtml extension, but with greater flexibility, and no worries if the LO version gets ahead of the writer2xhtml extension version, and no longer functions. (As has happened from time to time in the past).
For that matter, I suppose the import plugin should work with .odt files from other sources than LibreOffice or OpenOffice, perhaps with some tweaks of the config.xml file.
Great work!
Albert