Whether this is a good situation or a bad one will really depend on the particular NP. I'm doing a preceptorship in a family medicine clinic this year, and I generally spend about 1/4 of my time with a NP. She has her own patient pool, and fits in very well with the clinic physicians.
When I work with her, it's true that she isn't always able to answer all of my nerdy science questions. However, she often gives me the chance to do more things independently. Perhaps she just doesn't understand the level of relative incompetence that comes with an MS2, but either way, I appreciate the responsibility. Also, in my experience, NPs have also been more willing to discuss possible diagnoses with students and genuinely consider their feedback. So, I guess my point is that you shouldn't just assume that an NP would be a poor preceptor. Instead, maybe you could ask her if she would mind if you occasionally worked with her MD colleagues too?
This is what I find objectionable about precepting under and learning from NPs as a medical student - discussing diagnoses and treatment plans is one thing, but the student should have a very clearly-defined level of responsibility, ESPECIALLY at the M1/M2/early M3 level. Nothing should be asked of the student that the attending preceptor cannot handle him or herself.
My very first M3 rotation was family medicine. My MD preceptor's vacation week fell during my month at her clinic, and as a result, for part of my rotation I was "unofficially" re-assigned to her NP colleage (the clerkship director did not know about it as my MD preceptor did not mention it to him), who worked mainly out of a different clinic affiliated with a local hospital. That 3-day period was the most terrifying experience of my entire M3 year. This was a woman who had been an RN for 20+ years before going back to school for her NP, and had now been a nurse practicioner for several years. After explaining to her that this was now only my third week of clinical clerkships, she proceeded to ask me for pointers on the abdominal examination of a patient who, in retrospect, may have had something seriously wrong. Soon after, she asked me what antibiotic I thought she should prescribe to someone with a puncture wound and surrounding skin infection. Later that day, I was asked about the mechanism and side effects of Clomid before she prescribed it to a woman complaining of infertility. She asked me these questions not to "pimp" me, but because she herself had a knowledge gap and was uncomfortable with her own clinical judgment and decision-making, and she somehow thought that, because I had completed two years of medical school, I had a legitimate answer. We didn't discuss my Dx and Tx, with her then modifying the plan and providing teaching points, as I've done in all of my other rotations. On the contrary, she was asking me, the THIRD-YEAR MEDICAL STUDENT, for "advice" about how I though she should do the job she was allegedly prepared to do. That whole 3-day period was filled with episode after episode of me being thrust into very uncomfortable positions. There was no teaching, there was no pathophys, there was very little discussion other than her messy assessments which she threw together based on God-knows-what, and her reliance on homeopathic treatments, which really raised my hackles. I felt it horribly inappropriate for a preceptor who was supposed to be on-par with an ATTENDING MD to be asking a newly-minted 3rd-year student how to manage her patients. As a matter of fact, I was so upset by this entire experience that I went directly to my clerkship director and told him about it. He was furious and agreed that placing me in this position was completely inappropriate. He spoke to my preceptor about the incident once she returned from vacation, and I guarantee you that no student from my institution will be precepted by a nurse practitioner again on family medicine under his watch.
An anecdote, certainly. But my point is that a medical student should not be put in this position. Furthermore, I have NEVER felt this way under any of my attending physicians. Certainly, the "mock" role of history-taking and physical exam followed by coming up with an assessment and plan is invaluable, and students should present their entire HPAP as though they were the attending doctor making the decisions. But the bottom line is that the student has no real responsibility for clinical decision-making. That is what the attending is for - to provide the experience, the confidence, and, most importantly, the KNOWLEDGE to make proper observations, diagnoses, and treatment decisions for patients.
The bottom line is that you are learning to be a physician, and paying a lot of money to do so. You should be taught by physicians, not by nurses. Nurses are our colleages and should be respected as professionals, but they are not trained in the same way that we are. A nurse cannot train you to be a doctor any more than a dentist or physical therapist could train you to be a doctor. Nor does a doctor have any place training a student how to be a nurse or a dentist or a therapist. Can they teach you something about certain aspects of health care? Certainly. But you are in medical school to learn how to practice medicine, not to learn how to practice nursing. As such, you should be learning from a doctor. If you want to learn to be a nurse practitioner, the you should go to NP school. In my experience, I was uncomfortable with the situation, and I said something. I would do it again in a heartbeat. As a matter of fact, I wish I had said something sooner.