Personally, I think the o-chem is hardest. Does that tell you much? It shouldn't -- I think it's hardest because I've never studied it. I think physics is easiest; again, you shouldn't care. Certainly, don't decide you can direct your own study efforts based on what someone else says about difficulty. Study the stuff you miss on practice MCATs.
That said, I suspect that, among my students anyway, the kinda-consensus ranking from easiest to hardest would be biology, the chemistries, physics, verbal, though many would reverse the last two. The truly well-prepped student would probably say it's o-chem (because so little of it is the subject of MCAT problems), g-chem (again, finite number of things they test), biology (lots of potential for questions, including many confusing experiments), physics (should be easier, but I'm bowing to the opinion of the masses here), verbal (for which even the best-prepped student can't study any of the underlying material, hence can't be prepared in the same sense as with the sciences).
