I did both last semester and I liked Cell Biology much more. Everyone I know who did Miim20001 didn't really like it. It was a well-coordinated subject and all that, but somehow I didn't find the content that interesting (I really liked the immunology and virology bits but not the rest). I didn't write a review for MIIM because simpak pretty much covered most of what I would have said. Although, I should've done one because we had to two new lecturers who weren't that great.
I found Cell Biology much easier to do well in. There were no trick questions, everything was pretty straight-forward, unlike MIIM, and the content was easier to understand. There wasn't as much rote-learning and the lecturers were heaps better than MIIM. There were some tricky/confusing bits covered in the latter parts of the course, but lectopia and talking to lecturers helped a lot. Both subjects required you to know quite a bit of detail, though. But the exam had essay questions worth 50 marks. Some of them were broken into bits and they weren't really essays. More like drawing picture to explain something or listing something with advantages and disadvantages. Microbiology had short answer questions which were much easier to answer, but make up only 30 marks I think and the rest was multiple choice (like in the review) and fill-in- the blanks with a list of words like biology which were where the trick questions were included.
Even though I did much better in MIIM than in Cell Biology (91 vs. 82) I would still recommend Cell Bio to anyone because I really liked it. It all really depends on what you really like and you what you plan to do in third year.