I have seen conflicting information about how advanced the Nazis actually were. I know a lot of scientists were recuited to other countries after the war.
You may be interested in this similar earlier thread. https://www.reddit.com/r/AskHistorians/comments/5trbq6/getting_people_telling_me_nazi_military/ See responses by Blanglegorph, jonewer and myself.
The short answer is that any positions of relative advance (e.g. Rocketry) tended to be out of desperation, whilst Allied advances (e.g. Computers) tended to be more a case of doing things they could afford to do and which were a more efficient use of resources.