I'll second MarkJ on performance issues.The lag is profound, and the whole idea is to use it in an offline environment where performance is of ultimate consideration. IQ needs to get rid of lag, be fast and usable and only then are all the other bells and whistles of any import. It's a pity, but, Meh!
I installed the latest version of IQ today and gave it a whirl for a few hours. I then uninstalled it. 100% of the reason I uninstalled it was poor performance. I'm on a core-I7 machine with 16gb ram, and IQ had easily visible delays while moving around. The example database even took several seconds to display images on first load. Baah, uninstall!
"Improve performance" is a fairly big piece that could be divided into several components.
http://www.sqlnotes.net/drupal5/index.php?q=node/883 ... There are several other links on that page.