<p>Caltech requires five terms (trimesters) of physics (through quantum) and five terms of math (with lots of proofs). The MINIMAL requirements at Caltech are much more stringent, and the median student almost certainly works harder.</p>
<p>However, if you specialize in math or physics, for example, you will probably end taking equally rigorous courses at either school, so in that case the difference will not be large.</p>
<p>MIT is also a little easier on you in that if you end up disliking your quantum physics, etc., courses you can switch to another major and never hear of them again, whereas at Caltech everyone has to take them no matter what.</p>
<p>So Caltech is certainly harder on average, but whether it be harder or easier for you depends on what you would have chosen to do at MIT.</p>