Everything from the factories and trading to epic capital ship battles are done beautifully. But what a slow game.
The main problem X3 has is the speed and learning curve. Firstly the learning curve is practically vertical. Casual gamers find another game, its not worth it. People familiar with this fairly common aspect of simulators should be capable of flying and fighting within the hour even if not very well. Thankfully the X3 forum offers a lot of help that is lacking in-game. The speed however even when using the SETA time acceleration is glacial. Some maps are several hundred km wide and can take minutes at 10x acceleration to traverse. Even smaller maps average several dozen km wide and can are boring as hell to pass. Fortunately running the game in the background and auto-piloting to distant sectors is possible in the early game and late game sector jumps become vital to managing your sanity.
The game has some of the most artistically done space environments ever. The amazing environment backgrounds add to the game's addicting nature but are small consolation to the lethargic pace of the game. Beside environments all the ships and factories are gorgeous but once again after a while you get acclimatized. In general the artwork is beyond beautiful but if not played on a decent system can make the game's pace even slower.
Combat in X3 ranges from trading shots between your initial M4 and other small crafts to sending several boarding pods of marines onto a massive capital ship to huge battles between carriers, capitals and bombers that turn the screen into a huge explosion of victory. Combat is fun but the difficulty ranges immensely: early game you feel like a fly stuck in glue then your flight skills pickup you fly better and still occasionally get trashed but its fun once you upgrade your ship a little and as you get bigger ships you get beat less and less. Late game however no one can compete with you and your massive fleets are almost useless for anything other than destroying one of the main races in the game.
Economics is similar to combat. With hundreds of factories types and hundreds of regions to trade in, the scale is immense. But once again leveling issues are extremely prevalent. Early game you are too small to make much and spend a lot of time trying to make it but mid game you feel powerful though you still occasionally loss money and that makes the occasional hugely profitable sale a victory. Late game with a massive empire behind you with complexes containing hundreds of factories producing every type of good known to the universe and a massive fleet of thousands of freighters bringing your goods to ports all throughout the universe it gets just a little bland.
Put simply X3 is a beautiful game with an enormous complexity and an infinite amount of things to do. The community is full of amazing dedicated people producing amazing mods and scripts and helpful advice and tutorials. Sadly everything takes eons to do and by the time you've made your name in the game, you so sick of seeing the same art and hearing the same sound effects you just want to scream. To make it worse by that time the game is so easy, its boring.