Really great!
... for the first 50 episodes.
This is one of the first - if not the first - anime I've watched and the reason why I'm hooked on anime several years after rushing from school to watch this on TV when it was aired. A few months back, when, on a whim, I started re-watching it, I fell in love with it all over again upon watching the first few episodes. This is one of the best things about InuYasha - you don't need to watch 5 or 6 episodes before you get into it. The story starts right away, and you don't want to stop watching it.
However, I feel like it dragged on for too long and became repetitive. The main conflict was never resolved and the small conflicts in every episode got annoying after a certain point. It actually reached a point where, if you skipped 10 episodes, you'd know exactly what was happening and you'd miss nothing.
But not all it lost: if you're a patient person and used to long series like this, I'm positive you'll enjoy this. The concept isn't very original (group of strangers go off on a journey to defeat an enemy and encounter many mini-problems on the way), but it's still enjoyable. This is probably due to the fact that the main characters are very likable. Unlike other series I've watched, I liked all of the main characters and rooted for them.
EXCEPT FOR SHIPPO. I DON'T LIKE SHIPPO. THERE SHOULDN'T BE A SHIPPO.
The soundtrack is amazing and I have no complaints about the art. It's nothing fancy, but keep in mind that this is a fairly old anime.
Overall, I'd recommend watching this anime until you start to get annoyed by the plot drag. When you do, just skip to the InuYasha: The Final Act and watch the end. If you can watch this without getting bored, better yet! Good for you, mate, I admire your determination!