<p>All versions of 7.01x are theoretically the same difficulty. I didn’t find 7.012 (Lander’s class) to be a hard class. His lectures, though, are very entertaining =).</p>
<p>Office hours are for anything you want to ask about - don’t understand a topic as a whole, don’t understand part of a pset problem, want to make sure you got something right, etc. You can learn from other people asking questions, too =P.</p>