Add note that there are advantages to settings in .scala for multi-project builds

Getting-Started/Getting-Started-Full-Def.md

@@ -198,7 +198,7 @@ In `.scala` files, you are not limited to a series of settings
 expressions. You can write any Scala code including `val`, `object`, and
 method definitions.
 
-_The recommended approach is to define settings in `.sbt` files, using
+_One recommended approach is to define settings in `.sbt` files, using
 `.scala` files when you need to factor out a `val` or `object` or method
 definition._
 
@@ -214,6 +214,13 @@ nested project inside your main project. `.sbt` ("basic") and `.scala`
 build. More on that is coming up in
 [[Multi-Project Builds|Getting Started Multi-Project]].
 
+(A disadvantage of using `.sbt` files in a
+[[multi-project build|Getting Started Multi-Project]] is that
+they'll be spread around in different directories; for that
+reason, some people prefer to put settings in their `.scala` files
+if they have sub-projects. This will be clearer after you see
+how [[multi-project builds|Getting Started Multi-Project]] work.)
+
 ## The build definition project in interactive mode
 
 You can switch the sbt interactive prompt to have the build definition

Getting-Started/Getting-Started-Multi-Project.md

@@ -86,6 +86,10 @@ directory of that project_, while the `.scala` file can be as simple as the
 one shown above, listing the projects and base directories. _There is no need
 to put settings in the `.scala` file._
 
+You may find it cleaner to put everything including settings in
+`.scala` files in order to keep all build definition under a
+single `project` directory, however. It's up to you.
+
 You cannot have a `project` subdirectory or `project/*.scala` files in the
 sub-projects. `foo/project/Build.scala` would be ignored.