The extra Council missions are freaking brilliant; anyone who's experienced the whale mission will know what I mean. That damn think killed 3 of my top dudes on a normal ironman game where i was owning face and lost no one prior.
There is a demo for X3 if you want to test the waters. It shows a few different ship classes, mining and building/owning/managing facilities, basic combat, a bit on how the economy is simulated, ect. Keep in mind that the demo is old (2006!) when you give it a go in that so it doesn't completely colour your expectations for Rebirth, as from what they've said there will be some extensive changes to everything that X3 was in this game.
I have never been in any form of armed combat, nor can I saw I fully comprehend what that would be like, but hearing that ambush and that gunfire made me super antsy in a way a game never has. I can only imagine actually being there in an event like that and how much the disassociation can shift when playing a game like Battlefield.
I hadn't tried it until I saw this thread. Threw an Abra out there and got a Skitty. That seems super cool. I feel it's a better way to actually get a trade done than accepting the random trade invites that end up being people begging for your starter