A very fun addition to anyone's PS2 library. I was worried it would be all hype, but it's not. I had a very enjoyable afternoon playing it against my brother, but there is also the excellent Kumite mode that will keep me playing it single-player for quite a while.
It is hard though. Don't expect a system as easy to grasp as the DOA series, but once you start to get the hang of it, it'll knock your socks off. The very robust training mode is also helpful.