Max-on - I'd question the reason behind it. Yes, you get some increased breaking strength and decreased stretch and save some weight, but from what I understand - you pay A LOT for that. For safety (inspection) reasons I think I'd pick it over rod, but only if I was putting together an offshore racer and had a reason to pay the extra money.
Labatt, you may have not understood by question; the rigger recommended standard wire, I asked him about dyform, and he said it was not worth it. I was in a rush and late for an appointment that day and did not have time to inquire as to why, so I was curious as to the reason for his response. I did not know dyform is 'so' much more expensive, that is probably the reason for his comment.