Seems an update of this old thread is in order.
As many of you may know, MGM has recently released a new version of "GBU" on BD, at first only as part of this remastered Man with No Name trilogy boxset:
While the image quality of this version was significantly improved over the old MGM release, even beating the Mondo BD in terms of image resolution, unfortunately the "remastered" mono audio track was still just the downmixed 5.1 sound with the fake gunshots etc. However, last month, a standalone version of the remastered GBU was also released:
I can confirm that this version is *different* from the one that came in the new trilogy boxset. It finally has a real remastered mono audio track using the original sound effects!
For the scenes that were not synchronized in english for the original US theatrical version in the 1960s, they obviously had to use the new audio, but it was integrated as well as can be expected.
This release still has a few drawbacks, most notably a yellowish tint (in clear contrast to the more natural colors of the Mondo release) and the inclusion of the infamous "grotto scene" that Leone had cut out after the premiere for good reasons. On the other hand, it doesn't have the Mondo's wobble at cut points, and it has slightly better resolution (although I think they added some artificial grain). I had considered adapting my Avisynth script to synchronize the new mono track to the Mondo video, but after watching the disc last night I have reconsidered. In spite of the drawbacks, I think this is now the best release of this movie. It's also very cheap right now on Amazon, so I'd recommend to go and get it if you are a fan of the movie.