This is what I am here for too. Last night I left my laptop on for whole night and kept the import review tab alive for whole time. After almost 2-3 hours it imported almost 200 reviews for like 15 products only. Total progress 25%.
That means it does work, it does import but VERY SLOW. Also you have to keep the tab in front always. I recommend that once you click import the whole process should work in the back ground.