I see no one responded to this!
I would say absolutely get it. it is one of my favourite games ever and I think it has aged well. It's not brutal to play like a lot of older games now.
The general consensus I've saw is that the original Buffy game for XBOX is better. I actually do prefer this one - I like the areas and the ability to play as most of the characters (some are through the story and others available via multiplayer). I think anyone can enjoy this game - even non Buffy fans. I have it for gamecube and they say that was the best version but I don't know what the actual "differences" were in terms of performance/controls,
I've always considered this game canon because Joss and some of the writers were involved in the story, but I've saw some people disagree with that.
Let me know how you enjoy it if you do get it!