After 7 semesters of dental school hell, a voice recorder would have proved minimal usefulness in my dental education.
critterbug summed up why. Most of our courses had prepared notes that the course director provided prior to class or we had to print off the class website and bring them ourselves. Then during class, the professor proceeded to read everything on those handouts, word for word. In the basic science courses, they would insert an anecdote occasionally, or once in a while mention something not in the notes. In the dental courses, they sometimes supplemented reading the handouts word for word with some pictures demonstrating whatever dental procedure they were talking about. If anything in those classes struck you as "Hey, this isn't in the handout and I think I want to know it for later" - you just had to pick up your pen and write in in the margin of the notes. Not hard. No voice recorder necessary. If you can memorize every word in those notes, you will get a good grade. Dental school is all about memorization, there is very little understanding involved.
There were some courses, however, where the faculty refused to provide any sort of pre-printed notes. The student was expected to take their own notes to study for the exam. A voice recorder would have been helpful for these classes. However, I never really had time to go back and listen to the lectures. I found it easier to take notes as fast as I could during class, and compare them with my classmates to see if I missed anything. But if you are not a good note taker or have an atrocious time trying to handwrite anything, then maybe listening to the lecture later to fill in the gaps is a better idea for you in these classes. Maybe about 10% of our classes were like this.
So it really depends on the student and the course. My tape recorder broke after first year and I never replaced it. Looking back, it didn't matter. There was one course where my a few of us missed one class due to a research commitment. There were no preprinted notes for that class, you were expected to take your own. We were looking at the notes from three of our friends and they weren't making too much sense. One of our classmates who recorded the lecture very kindly loaned it to us, and I transcribed it for the others. That one time is the only lecture where having a recording made a difference. One time in seven semesters of classes.....
