I have had the 42mm since it was first launched. I use it for maps, messages, calendar, Carrot Weather, Workout and then for the notifications. I went with the 42mm so I had larger screen to use with my fingers. I also have Watch OS Beta, so I use messages a ton, and with the larger screen that I can select exactly what I want on the watch. I feel that if it were smaller, I would have a more difficult time using the watch apps resulting in me using the watch less. I tap on the watch probably like 100 times a day, so the larger screen for me was the correct decision.
I actually will say the 42mm is probably noticeable better with scribble since that has been introduced. I use it quite often on a 38mm, but I am sure it would be better on the 42.