The PU series was a good scope for the Russianintent, arm as many people with optics on their rifles to be better at the task then would have been possible with other scopes.
It was trial by fire in the Eastern Front verses in the West where sniper training and selection was still limited due to wanting to give only the best the expensive optics.
Which one is better? Neither, optics on rifles allows a solider who may not be "worth" getting a sniper rifle fire more accurately and precise with a scope on their rifle over iron sights. That is why here, and most everywhere else people make smaller groups with optics then with iron sights. And is why most Armies today equip just about every solider with a optically enhanced rifle.
But by the same token, when the choice is give your best shooters the training and skill they need to go into the battlefield and work well in the Western style "Sniper-Scout" role, a better optic and training is preferred as their role becomes less of a full time shooter, but more of a intelligence officer to report the enemies movements and other important information while they are behind enemy lines.
Dimitri