The Decklink card works like the canopus in that it will render anything not in its preferred codec and format. With a fast system I haven’t found this to be an issue. Then again, I spend more time in After Effects the PPro so I am use to waiting for preview renders.
I have the DL Extreme since we mostly work from BetaSP. Overall I think the card works great. Tech support is very responsive to any problems and the drivers are updated often.