I've worked with #Scala for 8 years. Currently working with the largest Scala code base I've worked on; 100kloc, 9 years old. By far the best written, I argue because of its Finally-Tagless style.
We have none of the original team left. Everyone except for myself is using this code to learn #Scala. Even with a lack of knowledge, nobody is inserting printlns, nulls, partial functions, etc. The types are factual and the Finally-Tagless style gives us great parametricity.
Ignore the people saying Finally-Tagless can't be exploited nor relied upon in #Scala. It's by far the best way to write Scala, not even a competition.