This is probably THE most popular Manga-Anime on earth, not only Anime-Fans like it, but others as well. Why? Because even though it is not always a very credible or spectacular series, the detective series and the overall realism of the series make this Anime so comfy to watch, everybody just has to love it!!! For instance, there is no character with blue or green hear and unlike other series, the characters to not yell all the time in an annoying, exaggerated manner.
The big pro of the series are the usually very cool and clever plots, sometimes an episode gives you all the hints you need yourself to figure out who the culprit is. Mostly though, an episode does not, or sometimes it's luck which leads Conan to solving a case. Nevertheless, the series is gripping, gives you false leads, is funny and the English subtitles with references and explanations to Japanese culture are excellent.
The series earns at least a 9/10. Personally, I gave it a 10, but what I don't like is that throughout the 506 episodes, the real core story about Shinichi and the Black Gang is rarely progressed.