I'm in grad school and I've been PRing since this summer. The most noticeable effect I've had is that a PR book feels "familiar" and new vocabulary and concepts don't slow me down as much. But as to reading with purpose, that is tough becasue my purpose is that I need to know the book well enough to access it for a number of reasons. Is it possible to have that as a purpose so that whatever paper I write now, or later, I can have some aspect of the book pop into mind? That is what I need as my courses relate rather than build on each other.
Also, I sometimes really enjoy reading the whole book if the writing is excellent, but I find I still PR because I feel I'm indexing the book into my mind. I guess that is my purpose with my books. Has anyone tried this successfully?
Finally, I've been doing some direct learning with kickboxing and writing books. I just PR them every few nights usually following a few rounds of EFT affirmations. Sometimes my kickboxing does seem to suddenly improve in an area, my punch or guard will shift successfully, but I don't recall anything from the book mentally so I wonder if it is just that or just normal growth from being in the gym.