I wanted to write something about how we now have a lot more choices in outfitting our ships, in not having to trade range for armor and stuff like that, but it's boring. Let me say something else:
After spending some time (and fish) in Beta, I've come to the conclusion that Engineers changes the game in a lot of subtle ways. All the loud talk about grind fests and NPC demons, overpowered shields and magic beam lasers drowns out the subtle atmospheric change the game has undergone.
I only noticed it when I switched back to 2.0 for a session and realized that, for lack of a better word, it suddenly seemed sterile. Contacts didn't produce unexpected scan data. Signal sources didn't say what was going on. My faction had no face. The graphics seemed less deep and lively. NPCs didn't run away. Stations didn't have traffic control voices.
And ships were all the same. My engineered ships now have quirks. Little differences from the standard versions: a little more heat sensitivity, half a second shorter spool up time, stuff like that. Stuff you can't enter in Coriolis. Barely noticeable until it's gone, but it adds a lot of character. Personality, if you will.
All in all, the game feels much more alive to me, not because of one huge change, but a lot of little ones. I didn't miss anything before, but I wouldn't want to turn back either now that I've seen them.