Excellent
I got into the space combat/exploration genre pretty late - I had the interest, but didn't have my own computer until 2000. Because of this, I missed all the X-Wing/ TIE Fighter and Wing Commander games. When this was released in 2003, it quickly piqued my interest - the exploration possibilities of an RPG, without the wizardry baggage that most of them came with. Freelancer did not disappoint.
Granted, I wouldn't say exploration is an important thing to do in Freelancer - you could easily stick to the story, stay along the trade lanes and jump gates, and you'll still have a blast. Combat is very easy yet fun - I don't have a joystick, but the mouse and keyboard controls were simple and intuitive enough to use. Trading is an easy way to make quick cash, although I wish the economy would be dynamic for added realism.
However, staying along the trade lanes and in populated space is like swimming in the shallow end of a pool. As you progress and pilot more powerful ships, you're going to feel like the big fish in the small pond. Travel to the Border Worlds and the Edge Worlds, and the difficulty increases (not too much though - the game is still relatively easy). The payoff is access to better everything - the best ships, weapons, and the possibility to make BANK in the trade of illegal goods. I loved how every system was laid out different enough that they didn't repeat themselves. While traveling from point A to B could get boring, it didn't bother me as much as in other games.
Of course, Freelancer has its flaws. The game shows it's age, although the game includes mod support, so I'm sure someone out there has spruced up the graphics. The story is generic (not too stupid, just boring); however, the characters were very two-dimensional. The voice acting of the main characters is good, but the voices used for space stations and generic enemies is skull-crushingly repetitive. Filler missions (between main story quests) are also repetitive. Just like my use of the word 'repetitive'.
With the combination of exploration, combat, and trade, Freelancer is an excellent space sim game. I would highly recommend this game not only to space sim fans, but RPG fans as well. If you find this game for $10-15, get it.