The most important improvements:
1. Ability to extract selected files from archive. For example, I'm keeping all test sets like 'Calgary Corpus' or 'SFC' in PIM archives and if I need extract only one or a few files, with this new version I can do that! In addition, now, if file already exists, PIM just skips it.
2. Two different archive view modes - List view/Details. Just another one cosmetic improvement.
3. Faster archive reading.