Ruby only needs symbols because it made the questionable choice of using mutable strings with by-object semantics. PHP does not have this problem. It will automatically intern literal strings, thus giving you the performance and memory usage benefits of symbols, but without the crutch of requiring a special syntax for them.
I think that special symbol syntax is nice, since it has additional semantic meaning in the form of "this data type here is used to represent a flag, not a piece of text".
Granted, Ruby's use of symbols is not as pretty as other languages...
