Just for comparison ED vs X3 pros and cons. I tried to keep it as balanced as possible.
X3: Tired of buying ships? Build a mining station. Now build the refinery for your mining station. Now build the manufacturing station for your mining station. And so on and so on. You can NEVER have too much money in X3 because there are so many money sinks, all of which are fun and engaging to participate in. Meanwhile in ED, I have no reason to leave the station. Let's be honest with ourselves, ED is currently heavy on grinding. The more I play ED, the more I want to play X3. Yeah I know what you are thinking, "beta". Well we will see if the final product will actually live up to the expectations.
X3: Dozens of vastly different stations per sector.
ED: Just a couple of very similar stations per sector.
X3: Can use accumulated credits to actually build your own stations and create your own business, or venture on the stock market, or hire wingmen, or create an entire army that follows you around.
ED: Can't do anything AT ALL with your credits except by more ships, a loop that makes no sense.
X3: Excellent single player experience, with many different things to do, all of which are viable.
ED: Boring and tedious single player experience with only a handful of things to do, with few being viable.
X3: A variety of alien life, when you received a message saying that the Xenon or Khaak are invading a sector, it's an "oh crap!" moment.
ED: Nothing like that exists, just faceless humans fighting for credits so that they can continue their endless ship upgrade loop.
X3: The faction system is simplified, but better. You have a trade rank, a combat rank, and a ranking with all the alien races. Every alien race has a plethora of ships that look and feel unique to their race, and you can only purchase better ones once you have ranked up with that race.
ED: Convoluted faction system, every solar system has five factions that have no personality whatsoever. Do I join "Styx First" or "Styx Organization" and even if I did, there is little to no gameplay effect from it.