I recorded uncompressed (RGB out) to my Blackmagic Decklink. 50i 1/50 shutter. At the same time I recorded to the card.
Looks like it is halfway smooth that way – at least on my preview monitor, coming from the timeline.
So for the moment 50i 1/50 it is.
By the way, I expected way more difference between those two.
It takes some color correction and a 200% magnification until you start seeing the artifacts in the AVCHD version.
Here is a screenshot and a 200% crop.
Left is uncompressed, right side is AVCHD.