The concept and setting of this circuit is extremely original and unique: Based somewhere afloat in outer space, not far from earth.
The actual track design is very good: There are no sharp angles or turns (no 90 degrees, etc.) -- all of the turns are very circular and non-geometric but quite varied -- making for a very good track with great flow...
The actual track graphical detail is very good.
A few faults seem to somewhat/slightly mar the overall race experience for me, which is why I don't quite give this track a 5-star rating: The space backgrounds (starfield, galaxies, quasars, planets, etc. etc.) don't have much depth or perspective; they all seem like somewhat unrealistic and cheap 2D objects that were clipped and added as low quality .gifs to the background. The earth however does look fairly cool and realistic.
Pretty much all of the replays throughout the entire track are shown from angles that are too high above the car; so most replays aren't that good; neither is a replay of an entire hot lap, etc.
Overall a very good effort; a cool space-themed unique circuit.