I like both. Big citites offer massive opportunities for personal development, learning, education and exploration.
But there is not much peace.
Small towns lack it but offer peace and often locals are limited in their tolerance and understanding for anything different.
The same everywhere I have been.

The best is to build your own house away from both :-)

But if you had to choose? Which city would you prefer. Barcelona or Madrid?
It's not a political question :-)