Ive been an evening student for the last three years and never had a problem, though I also cannot compare it to day classes!
In my opinion, I wouldnt say its harder to meet people, its probably that we are all of like minds in the sense that we (MOST PEOPLE) in the class are working full time and have a different approach to the subjects than that of day students.
In my experience many of us evening students are there because we want to be there to further our career... and VLTURBO is right, we are usually older but not that much older, im only 25!