I may be mistaken, because I have been playing around a lot with different things, but I ripped I am legend from BD and it was 32.XGB. I am pretty positive that I did that with MakeMKV, and just started. I did not unselect anything, turn up compression, anything at all except it start. I then used Handshake to make it smaller, again did nothing but hit start and it was massively smaller. I want to say ~5-6GB, but I cant remember exactly. My point is, if MakeMKV compresses at all compared to straight ISO rips it has to be VERY minimal.
Sean