The earlier review is WAY out of date. Memorial Hall was renovated in 2005 with updated seats, lighting, acoustics, sound, and, yes, air conditioning.
Every seat is great seat and I've seen nothing but amazing performers and artists on stage. From Alvin Ailey to Yo-Yo Ma to Brooklyn Rider to Angelique Kidjo to Bela Fleck. They also bring new and emerging artists to Chapel Hill. Tickets are affordable for the type of performers you are seeing and UNC students can get tickets for only $10!