When I listen to my recordings without ego, this means that I am listening for what I like and do not like. If something turns out nice, and I like it, that is good. If things are not to my liking, then I make a note of that too. I hear myself overemphasizing something, being too much on top of the beat, rushing through a melodic phrase rather than giving it its full value. The voicings could be muddy, with too much bass. Being a good musician is being able to listen for all of this.
The things I liked were some good voicings that sounded smooth and sweet, some melodic lines; the overall feel of things at times. The main thing is that it is my own taste that is the guide. I can hear something and say it is to my taste or not. The ego is out of the way in that I don't have to get upset or over-elated about what I hear. I can just try to keep the good stuff and not as much of the things I dislike. I hear a lot of players much better than I am who are not to my particular taste.