COMMENT FROM A 2007-ish THREAD ABOUT A AND E… Hope it helps.
They are equal in prestige and selectivity even though I don’t like to admit it. Many people say that Exeter is better for math and science, but Andover’s AP Physics classes are ranked first in the nation, so think beyond the stereotypes. The feel of the schools are very different. Andover’s campus is pretty spacious, spread out and has a more laid back feel while Exeter’s is more compact. I felt at home at Andover, but something felt a little out of place when I toured Exeter.