FWIW, here are some screen caps from one of my favorite Avengers episode (The Winged Avenger).
Sources are the last USA DVD release compared with what is currently streaming in HD on Amazon.
The older DVD release has many instances of dirt and other imperfections which have been cleaned up considerably on the newer transfers.
The newer transfers also have better color, more resolution, and additional information on the sides.
If the new USA BD release is using the same transfers that Amazon is streaming, I shall be very satisfied indeed.
The old DVD is on top. The new Amazon HD on the bottom: