string stream is slow. Quite very slow. If you are writing anything performance critical that acts on large data sets ( say loading assets after a level change during a game ) do not use string streams. I recommend using the old school c library parsing functions for performance, although I cannot say how they compare to something like boost spirit.
However, compared to c library functions, string streams are very elegant, readable and reliable so if what you are doing is not performance ciritcal I recommend sticking to streams.
