According to a survey of the surviving Jewish population taken in Poland shortly after WW2 http://www.bookgallery.co.il/content/english/static/book11132.asp opinions were split - some identified with the new regime while others felt bitter by Polish anti-Semitism. The latter feeling was fueled by the so-called Kielce pogrom http://www.jewishvirtuallibrary.org/jsource/Holocaust/Kielce.html which after the Nazi genocide was simply too much to bear, and was a factor often cited among those who opted to emigrate to Palestine.
I think that the stories of Jews "coming back with vengeance" are largely urban myths or right wing propaganda which used anti-Semitism to discredit the pos WW2 authorities.
In my own experience, I did not encounter much anti-Semitism in the socialist Poland, except perhaps stereotypes stemming largely from ignorance. I have not heard of anyone being socially excluded because of the Jewish origins, and of course no institutional barriers to employment or education existed. However, that started to change after the so-called "democratic reform," but this was clearly the work of the Catholic clergy and the right wing.
I would also like to add that joking about concentration camps was quite common in Poland and was not an expression of anti-Semitism - Poland lost over a third of its population in the war, so it was not just the "Jewish problem." I think it is a combination of two factors. First, "gallows humor" is often a way of dealing with unspeakable horror, and this form of humor is quite popular in Europe (and I presume elsewhere). Claude Lanzman (_Shoah_) missed that point entirely, e.g. in his interview with the locomotive driver.
Second, WW2 martyrdom was frequently used for propaganda purposes by the communist government - especially against West Germany. Poking fun of that martyrdom (including concentration camps) was a form of popular rebellion against government propaganda.
Wojtek