So what are the relative strengths and weaknesses of these two programs? DVDFab HD Decrypter is intentionally crippled in certain ways. It can no longer output as an ISO. It lags behind the commercial program in updates. And yet, of the two free programs I'm comparing here, it is the best option if you want a complete copy of a DVD-Video.
MakeMKV is not updated as fast as its main competitors, the commercial versions of DVDFab and AnyDVD, but it doesn't lag too far behind. If you need a decryption program that is updated whenever new versions of protection are found, neither of these free programs is going to satisfy you for long.
MakeMKV is convenient if you want a single file from a DVD. But you will lose menus when working with DVD-Video.
Comparing the two when decrypting Blu-ray, DVDFab HD Decrypter seems to be slower to analyze the movie. Ripping speeds seem similar. Both will do well if you want a complete copy.
Personally, I find MakeMKV to be easier to use, but I've never been a fan of the interface in DVDFab, as it has become more and more cluttered each year. MakeMKV is crude in comparison, visually, but simple is sometimes better. I do wonder how well MakeMKV handles seamless branching Blu-ray when making an mkv file, as it is something I haven't tried with it yet.
So my conclusion is that neither program is a complete solution for decryption and ripping movies. Which you choose really depends on what you need for output. Luckily, since both are free to use, they can complement one another, and it is never a bad idea to have more than one decryption program on hand.
Are there capabilities of these two free programs that I've missed and need some commentary? If so, please feel free to post. Or just share some of your experiences with these programs.