4Videosoft MKV Video Converter can be used to convert your MKV or MP4 files into a variety of other formats. The most popular formats, like H.264, MPEG-4, DivX, XviD, WMV, ASF, FLV, and MOV, are all supported. There are even conversion profiles for iPods, iPhones, iPads, and gaming consoles. The app comes with a video editor that allows you to trim and crop your videos and adjust their brightness and contrast.
Graphically, the app consists of a video player, a pane where the files on your queue are displayed and conversion settings at the bottom of the screen. The user interface seemed responsive during my time with it. In my testing, I loaded an MKV file which had subtitles and an audio track. I then trimmed the video to a 30-second clip. I also selected the English subtitle track that was in my MKV file to see if the subtitles would be hard-coded into the image. I selected the H.264 HD profile and started the process. After 2 minutes, the file was converted and the quality was very good. However, I didn't see any subtitles.
All in all, this app has very nice format support a good editor and it works well, with the exception of subtitles.