I've seen it... I think it is more of a novelty than anything else...
you watch it for a but becuase it is different, then think... why the hell am I still watching this?
The only thing that has ever really apealed to be basketball wise are the slam dunks and flashy plays .. other than that it's just a constant back and forth volley until the final two minutes.
The thing I like about Slamball is that the games are only 16 minutes long with 15 second shot clocks so you constantly have to keep the ball moving and pretty much every basket you make or miss is an important one.