I have SIGE 1.6 running and it almost works perfectly, the only problem I currently have on the live site is that I don't get thumbnails (red Xes on Windows and blue ?s on OSX) and I believe this is because the folder/file that is used for the thumbs does not have the right permissions. On the test site it works but there everything has 777 permissions, the live site is more protected and I only want writing privileges where I really need them.
Can you tell me what directories and files need the right permissions in order for the thumbnails to work? I can't seem to find the info on your website.
Other than that it is a very lovely plugin, nice work!