I don't know what form of mkv files those who gave this a 5 were converting, but it wasn't x264 based...
I've been trying this on and off since it was version 1 of mokgvm2DVD. I had EXACTLY one conversion come through correct and easily on the video portion, but the subtitles were screwed up (tiny with no way to change the size or position, yup I know about the options button).
However, probably not due to the GUI or tools in this package, it can't cleanly convert any of the stupid matroska files I need to convert. I actually have to give these to people outside the company to deal with. The video that results from this and it's previous versions have stalls, drop outs, jumping blocks and in ALL cases now, have a really bizarre form of horizontal digital streaking. My guess this is due to a popular windows x264 (not a compliant H264) codec that has no Mac/Unix/Linux equivalent, and it screws up like this due to improper header information and something critical in the actual image processing that is not completely compliant with H264.
On top of that, nothing I have given this new version (MKV Tools), can even get the subitles to burn into the video. Since everything I deal with has subtitles of one form or another, this is a deal breaker.
I do like the fact that matroska files converted with this maintain audio sync correctly, even though there isn't a single player out there that can maintain sync while playing the mkv files I deal with, live.
I'm sorry I can't give this a recommendation, even if the main problem is most likely with the idiots on the Windows encoding side, but a Matroska converter that can't convert matroska files to make them watchable (regardless of whose fault it is), is fairly useless.