i think it really depends on the professor. for me, our chem class was easy and straightforward whereas one of our intro bio classes was co-taught by three professors and only one out of three was actually competent. we had to do this ridiculous genetics group project that, while interesting in theory, was a huge mess because the server we had to go to to look up genome stuff kept crashing making the project nearly impossible. the actual material for bio, such as what is tested on the MCAT, is pretty easy and manageable but I think the extra projects and/or undelightfully eccentric prof can change that.
so, i'd talk to former students at your own school and see what the deal is there.