Differences in Digital Copy Sources?

[St. John Smythe]

Maybe I’m missing it here, but is there a list that covers the diffences in video quality betweeen different providers? I’m mostly referring to catalog titles. My two recent examples are:

1. The Longest Day - iTunes, Amazon, and MA don’t have it in the original aspect ratio. Only Vudu does.
2. The Maltese Falcon - iTunes, Amazon and Vudu all use an older, dirtier print, only MA appears to use the master from the Blu-ray.

Obviously, this is pretty frustrating, but nice that at least MA gives you all the sources, but you don’t want to find out later that you’ve been watching a poorer quality version. The wild card here is really Paramount, you won’t know which version you may be getting.