I did enjoy this series--it had a lot of fighting, some heavy symbolic gestures and repeating images/metaphors, and a rather sad/poignant focus on loyalties (does one honor love above all else? And if so, which kind of love? Filial, romantic, familial?). As the plot twisted around itself amidst some heavy betrayals and deceptions, I would become interested in characters only to be shown their tragic demise. This is not a light-hearted romp! It is, in fact, one of the more violent and brutal animes I've watched. But, there does seem to be some rather skilled story-telling here as well. I enjoyed the pacing of the series, and the way characters' special ninja skills, backstories, connections, etc. were revealed. Although, I did enjoy it, I don't know as I'd put this on the list of my favorite animes of all times. It was good, it was thoughtful, but it stayed just shy of becoming something I could see myself watching again--perhaps due to the violence? Or perhaps the animation style (which does seem older and grittier)? Or maybe it is the guy who fights with his nose hairs?
If you are interested, as many people are, in warring ninja clans, this is well worth a watch--it is rooted in at least SOME historical reality and does not shy away from serious brutality and heartlessness. Just don't expect a feel-good romp.