Rated 4 out of 5 stars
Works really well. Two things:
I'd made some highlights on a page, when I went back to the same page later some content had been added and all the highlights had vanished. I had to right click > 'remap' each one in the sidebar, which worked fine. It would be good if there was a 'remap automatically' feature, or a 'remap all in folder' command, or 'remap all on this page' to save having to do each highlight individually.
Firefox Sync support would be nice.
Apart from that it's great!