Currently, it’s difficult to understand what crf value you are setting with the “quality” option.
The quality percentage represents the crf from min to max. For example, in h264 crf range is from 0-51 (lower is better quality). 100% is 0 crf, 0% is 51 crf. 65% is 65% of the way from 51 to 0 (18).
It makes it seem like 65% is losing a lot of quality when really that’s at the point where it is said to be visually lossless. This may confuse new users and those unfamiliar with video codecs.
Show crf value next to quality percent would also help experienced users set their crf faster.
Currently you can set quality then click the plus button to add a new preset. You can then see the crf option without finishing adding preset which is a nice trick to help find crf without doing the percentage math.