<p>The answer really depends heavily on your intended major/area of concentration. If you are considering STEM fields, grade deflation is really a non-issue as grading tends to be difficult at either school. Having said that, STEM fields are overall considerably stronger at Princeton. If you are considering humanities you will find the grading at Yale considerably more lenient. </p>
<p>I would caution choosing one school over another based on grading systems. If grades are really that important to you, perhaps you would be best served at a less selective school. Princeton and Yale both have far too much to offer and far too many strengths to compare to let the decision ride on grades.</p>