Consider this... I have had so many problems with the multibridge on both PC and OSX that i would never ever buy anything from decklink.
multibridge does NOT support uncompressed 720hd 30p or 24p. It does NOT support realtime up and downconversion on capture and playback on the PC. Tech support is horrible.
With aja, I used a kona 2 for a year at a production company and the sdi in went out after intense use. Called up aja tech support. They walked you through trouble shooting, unlike decklink that will just try to usher you off. After tech support agreed there was a problem, we were sent a brand new replacement and had 10 days to return the old card after recieving the new one. No down time. I just used another machine to capture but could still work in realtime uncompressed on my usual station. That is fantastic service with consideration for the time constraints of video professionals.