Thanks - QuickLZ does look good, unfortunately we're planning to release certain versions of the software we're developing under GPL and others under a proprietary license, and the $1200 for QuickLZ are a bit steep for an as-yet-unfunded startup. (this is the only time so far that I'm wishing I was a lone founder ;-) - the license would only be $100 then)<p>BriefLZ on that comparison page caught my eye, however. It uses the same license as zLib while being more than twice as fast. We'll have to test that, it would be a good starting point. (and the code is short and clear enough to be understood and reviewed; can't afford to have buffer overflow bugs in it) We can upgrade to QuickLZ or LZO later when we can afford them. Somehow, BriefLZ that seems to have been missing from all the other compression comparison pages I've looked at.