I watched it today, and I gotta say I'm kinda disappointed. The PQ of the BD is better than the DVD, but not a huge difference. Also, while the colors of the BD are richer, the DVD is noticeably brighter, so you end up missing out on a lot of the extra detail, due to the BD being so dark. On the plus side, they seem to have cleaned up the print, because I noticed that in the scene near the beginning where DeNiro is talking to John Voight about the armored car job, there was a hair or something at the bottom right of the screen. You could see it in Voight's suit. This hair was gone on the BD.
I would say the audio is more of an improvement over the DVD than the PQ. I wouldn't call it oustanding, but there was a noticeable difference in the impact of the guns in the downtown shootout scene.
All in all, it's a pretty good disc, but not the big upgrade I was expecting.