To be frank, although I enjoyed Scorcese's Mean Stretts, the film did not leave a lasting impression on me.  This does not mean that the acting was poor, rather the script was somewhat simple and unpolished.  Scorcese took a lot more time on Taxi Driver, and this is apparent throughout the entire film.  To begin with, the music score by Herrmann compliments the tone of the movie perfectly and conveys a feeling of loneliness and drifting.  Secondly, the strength of DeNiro and Keitel's acting has improved considerably.