To play devils advocate, the benefit to MKV is being able to include odd audio types not allowed by avchd such as flac, and strange subtitle formats such as .ass. Again, if you want a flac mkv, it is extremely easy to mux yourself. MKV is a kitchen sink, it supports everything. AVCHD is a common denominator supported by every device natively, but it is more restrictive as to what audio/video is allowed. Since Harmy is releasing 1280x720 h.264 video and ac3 audio (which is bd compliant), he is not using any of the additional features mkv offers that avchd does not. There is almost no benefit to using mkv over m2ts (a slightly smaller container overhead, a benefit which would be negated by forcing harmy to upload two of the same file) because virtually any device that supports mkv also supports m2ts, but not the other way around. AVCHD is the more standardized format, supported by more devices, natively. It makes sense to only release in one format instead of uploading two of the same file. It would even make more sense to release in MP4 than MKV (then even browsers like chrome and safari could play the file) except that MP4 subtitle support is iffy. AVCHD is better supported when it comes to subtitles. I am just repeating myself now, so I will shut up. If you have any questions reread the thread, everything has been explained multiple times.