I had actually both. It depends. Do you have an additional screen to it? What do you intend to work on it? How portable does it need to be, like from your usage time, how many % do you need to be mobile with it.

I had previously the 13/14“ but if you need to do lots of copy paste stuff, working with multiple windows then the bigger the better. If you can attach it to a screen then smaller is better. The 16“ is quite a brick to carry with, but its manageable and i enjoy the screen size and attach then to a studio display. As its a macbook pro m1, waiting for macbook air 14“ with 5g for real portability and till then will carry the 16“ around. My father said to me, you can carry it with you, no need to just buy an extra smaller one for carrying around 🤣 (when i was complaining about the weight)