Can you elaborate on why someone would pick the Sabre as opposed to the Hornet, and vice-versa? How does this relate to the Hornet Ghost specifically?

The Hornet is a tank, it's not particularly mobile but can really take a pounding and make it out which is a great feature for a lot of players. Its similar in my mind to how current day pilots love the A-10 for its rugged reliability and ability to come back home with huge amounts of damage. The Sabre on the other hand is not tough, it relies heavily on its ability to not be detected and then its array shields to keep it safe. Once those shields are down you'd best be on your way out of combat else you'll probably not make it back.