I've played Drifter for 70+ hours pre-Steam, and while there is a steep learning curve at the moment and a lack of content in some areas, the level of detail and the all around playability already make it one of the better space trading sims out there.
One of the first things you'll notice when starting a new game is that your ship follows the laws of momentum, and doesn't come to a full stop every time you thrust in a different direction. Couple this with projectiles and energy weapons that take time to reach their target, and you get tense and often disorienting battles, fighting as much with the laws of physics as with the pirates that want whatever it is you have.
Outside of a few core systems the galaxy is procedurally populated with star systems and destinations, some friendly and reliable, others viciously hostile teeming with marauders. there's trading opportunities everywhere, and it's up to you how safe you want to play it.
As for the trading, it's a steady if slightly shallow source of income. However the framework for it is in place, with regional price differences and the need to balance what you can carry with what will make you the most money, and with this being Early Access new content is always in the works.
Like with trading, the available missions are steady cash flow but a touch mundane, with patrol missions being the preferred combo of seeing new places and blowing up things.
All in all, the fanatical level of polish and the overall level of detail, combined with the devotion of the devs and the steady stream of new content make Drifter a very highly recommended purchase.