I haven't done a direct comparison test but I do have a ~50yr old can of Unique that I used for case forming loads in 7mm-08. Compared to QuickLoad predictions, which are obviously based on the new stuff and are generally scary-accurate in bottleneck cartridges, the old stuff was considerably slower fps than expected.
That, and the gun looked like I dragged it through an ash bin.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.