[szatkus]

Both are equally readable to me, but with the builder pattern you have an ability to fork a builder. Cloning objects in Java could be messy.

[stickfigure]

With immutable objects, every step in the fluent chain of calls is an independent fork of the full object state. There's no need to use java clone(); each method calls a private constructor that passes the object state (slightly altered, of course).

java.lang.String works exactly this way. You're already used to the pattern.