I find that teaching biology at the college level is very rewarding since some of the students actually want to be there instead of being forced to be there. Sure, some only take biology because it's required of their major but the few students who are interested make the effort worth it. Some of the pros of teaching biology is that you get to teach a variety of different subjects, you are not teaching all the time but get to go outside and do lab work, and you can grade papers from the comfort of your home. The main con is that it doesn't pay that much; but hey, bet hey, most teachers will tell you that they don't do it for the money.