The lunchtime slot would generally make it more difficult for me to attend. With the meetings in the evening, I don't have to make up the time at work. Furthermore, given the unpredictable nature of job responsibilties and work related meetings, I'm not sure I could count on having almost 2 hours in the middle of the day.
While I have potential conflicts with work, what about students? Given changing class schedules, I would think that students would have an easier time making a 7:00 pm meeting than a 11:30 am one.