I think it's crap because of how it's designed. No template system. 400 files which are updated daily. The language/text is all embedded in the PHP files, so if you want to have French, that's ANOTHER 100 files. Every time you download it, you get a hundred useless CVS tag files and an entire example shopping cart store which all have to be weeded out before you upload.
There is no such thing as a bug-free, feature-locked version. Instead it's just feature creep with bugs fixed along the way. There is no stable branch of the CVS, just whatever they've grafted features and bugfixes onto. So if you are asking someone for help with it, chances are, the version you're running will be just different enough from theirs that they can't help.
They tried to do a Milestone release version 2.1 but there were a dozen serious bugs reported and fixed only in the CVS version within 24 hours of its release.
Those guys need to get serious, go templates, cut the # of files by 1/2, the number of MySQL queries by 2/3, and do point releases.
