I've talked to two people about it. They both said cell biology is better in terms of the difficulty of the course. This comes mostly from the professors as those who teach genetics at my school, are subpar. They also added that the labs do not correspond well with the lectures, and that the coordinators and TA's are not very good. One of them did say that genetics was mostly high school stuff though.
Another thing is that if I go with cell biology, I'd have to squish two second-year chemistry courses into one semester. So, I'm stuck in a pickle: I could either take genetics and be able to divide my chemistry courses into two semesters, or I could take cell biology in the first semester and then take two chemistry courses in the second semester.