This anime is really good. One of my favorites this season. It's basically everything that Gundam Wing should have been, but better. Way better. Both share a politically driven story and a lot of the characters are similar, but the main focus are on Terrans (Earthlings). Here's a short comparison:
GW:
Humanity colonizes space
AZ:
Humans colonize Mars
GW:
Space federation declares war on Earth. Operation Meteor
AZ:
Mars declares war on Earth. Operation Earthfall
GW:
Cold, calculating, emotionless main character from space and lost princess of Earth
AZ:
Cold, calculating, emotionless main character on Earth and lost princess of Mars
GW:
Space Colony equipped with superior and advanced Gundam mobile suits
AZ:
Mars equipped with superior and advanced Aldnoah mobile suits
GW:
Main character eventually pilots Gundam Wing Zero
AZ:
Main character eventually pilots Aldnoah.Zero (my guess)