Played this for a few hours yesterday and enjoyed it a lot. Let me preface this by saying I did still enjoy the game when it was released, rough edges and all, but I think with this update they are much closer to what people were assuming the game was going to be like from the beginning.
It's really a collection of mostly minor improvements, re-balancing, etc, but the whole of the game is much more fleshed out it feels like now.
Biggest things they added:
+ Multiplayer. Not open world like Elite at the moment, but you can pretty easily meet up and travel around with your friends now
+ 3rd person camera and a customizable avatar. You can look like a human, one of the 3 main races, or various really weird aliens
+ Much better terrain generation. Each planet doesn't feel like a cookie cutter of all the other planets with a different skin pasted on.
+ Real base building. No more boring quest line to get a base... you build a base computer, place it where ever you want, and you can start placing floors, walls, roof, etc nearby. I will say... it's not quite as customizable and fully featured as Empyrion, but it's still a huge improvement of the old system.
+ Better graphics. Empyrion's update made that game look much, much better, but NMS still takes the cake here. I was on a small moon orbiting a planet with rings last night and it was awe inspiring.
+ Revamped crafting system. The names of basic materials and items are much more clear now and make it much easier to see what you need to progress
+ Mining is much, much easier. Resource nodes are smaller, but far more plentiful and easy to find. Each planet is also clearly labeled as to what resources you can find there
They also seem to have lowered the bar for getting at least a basic freighter. I was following along the starting quest, and jumped into a system where a freighter that was under attack. I helped them, and the captain invited me aboard and offered me ownership of the ship. It gives me a mobile base, a place to hold extra ships, the interior has a changeable section where you can build new rooms for the freighter, and there's a fleet system now where you can buy frigates of various types to accompany your freighter giving it different bonuses.