We bought it to automate our release process by running off Quicktime, Windows Media and Divx versions of our vids automatically. It can't do that - it doesn't play nice with Quicktime 7, and crashes with unexpected errors whenever you ask it to encode an H.264 video. It also sometimes mysteriously crashes when running out WMVs.
We also wanted it to convert our AVI files to Quicktime for Final Cut Pro. It can do that - most of the time. I reckon it crashes about 1 time in 4. However, it can't handle input files with different aspect ratios - it just automatically puts black letterboxes around the edge of some of the videos. It does this, by the way, automatically, and there's no way to turn it off, according to Canopus Tech Support.
(Virtualdub, which is FREE, handles the problem without incident. Oh, how I wish there was a version of VDub that would handle Quicktime.)
And, just now, it won't convert 2 files with inpoints and outpoints into Quicktime. No wierd aspect ratios, no odd codecs- we're using PNG, for heaven's sake - it just crashed out every time with a "QT Writer Error". Eventually I did it in Premiere instead. Because it was easier.
So, if you're reading this and looking for a decent video conversion package, for the love of whatever deity you choose, buy Cleaner XL. (We would, but we can't afford another three-figure purchase right now). Or code your own. Or use Compressor. Just don't buy ProCoder. It's possibly the worst, most buggy commercial package I've ever used.