The MEPS "medical exams" were more like a rush-job of a bunch of retards trying to hump a doorknob. Do you have teeth? Good. Do you have eyes? Awesome! Can you walk like a duck? Perfect! Piss in a cup, draw some blood, do a quick hearing test. Bend over and grab your ankles. Most of my day was spent waiting for the next station.
NAMI was very extensive. Full vision test complete with cyclogplegic refraction (eye-dilation), color-vision, depth perception and the rest. There was EKG, hearing test, blood work (I assume cholesterol and CBC), Aeronautical Adaptability test (valsalva demo and balance demo) and and a flight doc consult in which you'll actually sit down and go over your medical history and/or any issues you may have. Anyone chime in if I'm missing something. I probably spent an equal time at NAMI, except a lot more of my time was actually doing stuff instead of waiting (although there was a lot of waiting).
That's what I went through for my MEPS with the exception of the pupil dilation albeit I was tested at Branch Med at NASP. But yea that sums it up.