If you are going to get loupes, dont limit yourself to whatever reps pimp your school. You'll only spend 4 years at that school, and if you take care of them, you use the loupes much longer than that.
Most respectable loupe companies have a trial period, and if you are not happy, will allow you to return them. I suggest trying on several companies loupes.
Looking at your hands in front of your face is what most people do when trying out loupes. However, I suggest bringing a sheet of graph paper with you. Keep the loupes 'aimed' at the center of the paper and move your eyes, not the loupes, and check the periphery of the lenses. Many loupes are fine in the middle of the field of view, but loose a great deal of clarity and color correctness as your move out of the bull's eye, so to speak. In my opinion, all the lines should be clear even at the periphery, and there should be no color aberration. More on that
here
Maybe distortion and chromatic aberration are not priorities for you, but the way I approached it was that I would be using these loupes to improve my vision, not distort it.
You'll also get a lot of folks who say that you have to get X power loupes for everything. Hogwash. You wont have one handpiece for every procedure. You wont have one endo file for every tooth. You wont have one restorative material for every patient. I feel that limiting yourself to one certain magnification for every procedure is silly. I use 2.5X for general type procedures where I want to see the entire quadrant; I want to know where my bard parker blade is, not guess. I am planning on a 5 or 6 for endo type procedures, but that will come later.
