One more vote for the AJA IO. I bought this unit over the Decklink Extreme.
I never thought I would use the S-Video in, but sure enough, it saved the day on a job recently.
Also, having the connections on a rackable unit is preferable to a bundle that hangs off of the back of the computer.
The fact that the IO ties up the FW bus was solved with a FW800 PCI card.
To me it was worth the money for the flexibility and convenience. It depends on your application, gear set, and client needs. BMD cards have a good reputation, and I've used them on rental systems and have not had any complaints.
I have not dealt with BMD tech support so I can't compare, but I will say that my experiences with AJA tech support have been very good.
Tom