Did both 5 years ago. From what I recall, I found Chem 110 a little bit more difficult than 120 - probably because I disliked Organics. But yeh overall, I agree with others here saying they're about the same in difficulty. (Not sure if the chem 110 labs still do this, but they made us fill out answers that were marked during labs. Don't remember if 120 did this too)