I gave a presentation on this topic at Rubyconf Brazil last year, and would be hard pressed to describe Ruby as "good" at dealing with Unicode, unless by "good" you mean "avoids making almost any decisions at all" (which might actually be a good thing but it's debatable).

Ruby 1.9 doesn't even offer Unicode case folding, so from a practical standpoint working with Unicode text is a PITA with Ruby unless you use third party libraries.

Ruby source can include constants, variables, etc. with Unicode (or other character set) symbols, which is very cool but for Unicode text processing I've found Ruby to be frustratingly lacking.