I didn't question the condition of the Star, only the WaA stamp. The gun is very nice and the 600 is just downright pretty. Those Astras are nice guns, but the recoil isn't so nice. The 400 especially can be downright nasty.
The Star is different from the Colt in several ways, some improvements. The safety cams the hammer back off the sear rather than just blocking the sear; if the gun is dropped on the hammer while cocked, the sear and hammer notches won't be destroyed. The slide stop spring and plunger are different, but not necessarily better.
The trigger is pinned; that prevents "trigger bounce" which can drop the hammer in the half cock notch when the slide is released and not eased down. That doesn't happen with a pinned trigger.
The main change, for good or bad, is that the back of the grip is solid, with no grip safety and no separate mainspring housing.