Analysis: Drawing someone is worse if you know them. Plain and simple. Then it is not about quick sketch or drawing what you see. It becomes more about does it really look like them, or in this case: is the sketch cute enough because the kid sure is. Philip and Jenny, your kid is MUCH cuter. :) It's his lips...extremely cute AND distinctive, but a pain to draw and have look right. Also, I got the angle to the eyes and mouth, but missed it slightly with the nose.
The part of my daily sketch that people normally don't get to see is the drawing overlaying the picture. I don't post it because of copyright issues, since I am drawing faces from off the web. I did pretty good with proportions of the face, except for the jaw line. Gavin has chubby cheeks. One day I'll be better at the proportions, after a couple years of daily sketches :)