I'm ready to pull the trigger!
I must adnit I am biased. AJA makes reliable solid equipment and has the best tech support. My experience on the Mac with the Kona 3 card and CS 6 has been a very positive one. You pay a bit more than BM (that sounds gross) but I feel better about the product all the way around. Now I use it in conjunction with a Panasonic "engineering" monitor which takes the SDI out of the Kona 3. Your needs may vary from mine.
I am anxious to see what the the system builders like ADK and Safe Harbor
end up integrating into their graphics / editing workstations.
...along with the power users like Harm and Bill.
Looking forward to seeing the new drivers in action. I tried a Kona 3G card a few years ago and lost all realtime playback when working with Red media since the Kona timelines in Premiere CS5 didn't enable the Red Rocket card. Mecury Transmit sounds like it will solve this as you're no longer needing to work with Kona timelines.