Although this is one of many converters out there, the strongest features of this one are that it can convert large AVI, MPEG, MOV and RM formats to WMV ASF. It's also unusual in that it supports large video files, even those larger then 2GB. You can literally batch convert hundreds of GB of films and data in one go without having to re-prompt it at any stage. It's very quick and to top it all, it even looks good with a very nice Mac-style interface with big glossy buttons.
To convert you simply click on "Add" and you'll see the file in the interface window with a clock next to it. Choosing the format you want to convert to, hit "Convert" and you'll see the clock change to an arrow and finally to a green click when done. A handy conversion status bar lets you know how far the process has elapsed. The only problem I found is that sometimes, you get a "Failed to Initialise" message, which is usually because of Codec problems.
However, if you have at least Divx 5.x Codec for the DivX MPEG-4 format file installed plus the Xvid Codec for Xvid MPEG-4 format, you should have no problems with this excellent converter.