InuYasha is one of thoughs animes that you either love it or you hate it. I am one of the ones who love it! I have been watching it since I was 13 years old. I gave the story a 9 because it is so long and it does have some fillers. Everything else is a 10! Because of the 9 on story...overall it is 9.9.
The ending will get most of the fans a little angry...I was. (I mean season 7 end) I will not give spoilers as to why you will probably get mad...but just know that you might. The KagomeXInuYasha piece to the end is very cute though...I must say.
Like i said...it is very long. I have been watching for years, and I don't think I have seen every episode...(160+). I did not watch it in order though so that could be why I am not sure that I have seen them all.
In order to understand the series...I would say that you should watch it from beginning to end in order.
Overall...a great anime!