I have the Hoya FL/ MC (multicoat) 72mm filteron my 711XU. Bought it 3 weeks ago in person at B and H Photo in NYC for $32.
It's benefit is in getting somewhat richer colors and somewhat darker blacks.
It's drawback is that it cuts back on light output. So I use it when viewing "bright" movies. Definitely don't use it for darker ones (Gladiator, U571).
Bottom line on the filter...It helps on ocassion, but I don't think it's that big a deal.
