The crowd isn't usually a good indicator of how good the food is.

Not in tourist places. However, you want to eat where the locals eat. This city has very few tourists :)

Since I'm a big eater, I would usually prefer a good cheap restaurant that has big servings over an expensive one with small servings, even if the latter tastes much better.

This is the same for many Finns. They want a buffet where they can eat all they can fit in.