This game has big potential. It seems to aim for the same or similar goals as Elite, the old space sim from decades ago, but with randomly generated galaxies, ship building, and third person mode.
For the point the game is in now, it is kinda empty. It has ship building that works, and I love it :) Flying on the space works too, but it is kinda useless because combat seems to be hard and buggy and didn't understand the idea of that MDV thing. But for the shipbuilding, I would pay this price for only that part. It is really cool and customizable, and you can spend hours building your dream ship. Be it a fighter or a full-scale capital ship. I see this has so big potential it will turn to be very great and popular sandbox space sim, but that is yet to be seen. If you think 20 bucks is too much for this, because you won't know if it will be ready, then just wait for the summer sales to come up sometime in this month and buy this from there!
But I recommend to buy this, it is really awesome game!
And you should look at the screenshots section for some f*cking awesome ships. Might get you an inspiration if you don't know what you want to build :)