In what respect is it better than an Audigy2? I've had this card for years and have the itch to upgrade..but I don't really see why I should.
When I upgraded from the audigy 2 to the x-fi music about 2 years ago the largest difference I found was in MP3 playback. I could make them sound crisper and smoother, just more fun to listen to. Other than that I can't think of one thing that the x-fi really did better, at least not to my ears.
As for Windows 7 I have read there are volume issues with an X-fi as in your volume will sound really low. I have read some fixes and will try them myself now that I have an 8-pin 12v extension and can fit my x-fi into my case again (switched PSU's, cable was too short and would not allow me to have any pci cards installed). I'll see if it has no issues with Win 7 64 bit though from what I read it should not.
Great card for a decent price, though this is what I paid for mine, also from Amazon, 2 years ago.