Had an interesting evening of viewing. I began with THE THIRD MAN in Blu-ray. I just rewatched the regular DVD version a few weeks ago when I reviewed the Rialto Pictures box set from Criterion. The Blu-ray is the same transfer, just with much greater resolution. It looks as wonderful as you might expect, but it's certainly not perfect. Blacks aren't the blackest, and the print they used had a few stray scratches, some water spots, and a thin light gray bar running down the right side of the picture for half a minute or so.
They used uncompressed audio for the soundtrack (at 1.5 Mbps - the highest I've ever seen for a mono track), so it sounds very clear, but, of course, there's still hiss and some light flutter occasionally. But those things fade in the background as you get swept up into the movie.
It's one I NEVER tire of.