I play both really. CN has its benefits. But the only time CN really heats up is just before and just after server time 00 hour. (attacks are most effective here) Thus you won't worry too much during off hours about getting hit, but there is very little counterattack capabilities. It's pure random. The tactics are fairly simple; 2 CM strikes, 2 bombing runs, 2 land attacks, 2 land attacks, 2 bombing runs, 2 CM strikes in that order. Then there's the manipulation of the Defcon levels that most people already realize. You can usually get by without knowledge of too much of the politics.
AE tends to be more of an anytime goes, but obviously that tethers you to the computer during a massive war. But it's really nice hitting at around 2 or 3 in the morning (US time), where there are very little players. I often did so during the NPO vs Borg war, especially debris stealing from people. Also, counter-attacks are very very effective if you are online at the same time as the opponent is, for many of their strategies revolve around a sleeping opponent. Otherwise the defender usually can counter the deadly fighter swarms by pulling their fighters and weak ships out, and let the big guns smear their fighters, and strike their carriers and recyclers as they rebase nearby. Also, politics is key. It tends to suck when you come back and half of your bases are occupied, your fleet is down 40%, and your opponents already stole the debris.