I've asked similar questions in the main TravelPro Crew 8 thread:
http://www.flyertalk.com/forum/trave...-crew-8-a.html
As far as I can tell the only substantial difference is the warranty - the rest of the differences seem to be subjectively taste related.
But note the post where Crew 7 is rated above Crew 8.....
And no, I haven't made a decision yet either....