SP1 Upgrade to ISA 2004 worth it?



I'm running SBS 2003 Premium c/w downloaded SP1. If i want to upgrade from
ISA2000 to ISA2004, i'd have to order SP1 on CD from microsoft. Q. Is
ISA2004 much better than ISA2000? Is it worthwile to get? Any tips /
Suggestions?

thanks,
w


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