 If you liked
City Hunter
|
 ...then you might like
Master Keaton
|
Both main characters are professionals and helping others by completing their requests. City Hunter has more of fan service, women, guns and is a shounen type of anime while Master Keaton is more serious type of anime. Both animes seems to also be episodic.
I would say City Hunter is much more enjoyable to watch but it does not hurt to watch them both.