Not hard to use since you only have to browse which video file path that you want to repair, then choose the repair option and let the process complete. As soon as its done, you can take a look before saving it. It also works on read-only mode, so no damage or changes are made to the original AVI video file while it's being repaired.
They have a free evaluation copy that you can download and try. You can check the speed and performance of the software, then if you like their product after, you can purchase it.
If you need to repair several videos at the same time, all you have to do is select the files and queue them up, then click repair. It also supports WMV, ASF, MOV, MP4, M4V, 3G2, 3GP & F4V file formats.
You have to know that the free version is very limited and can only work with files smaller than 10 MB. Also, you won't be able to save what you repaired, though you can preview up to one minute of video footage. You have to buy a license to remove all the restrictions. Take a look at picture number 3 at the top of the page.