the question is whether a normal person will detect the difference in a way which will affect their enjoyment or experience of whatever they are watching.

otherwise - it more an issue of what you have to connect to.
if you are working in a professional environment with sdi, then you will want an sdi input.

If you arent using and investing in sdi, there the analogue cards seem ok to me. the low cost cards seem fine.
but i havent checked in a critical application.

with video input spending more money doesnt necessarily get you a 'better' image - with the current crop of cards.

i mean there is obviously a difference between a composite and an sdi source in technical quality.

im a fan of low-tech imagery. i like watching super-8 expermental films - i like the image when its distorted.

i dont like things to be too clean.
ultimately the decisions are expressive decisions.