Both engines are finished.
Left: the brasin one; right: the one of the plastic kit.
2nd and 3rd photo: kit engine
4th and 5th photo: brasin engine.
As you can see, the brasin engine is very fine and looks from far (from a "different galaxy" as it seems to me!) better than the one of the kit.
I must honestly say that I find the kit engine poor and too basic. If you wish to realise a very fine Schuckert, you must buy the brasin one.
On the other hand, the brasin one is not easy to assemble. There are many PE parts to add and the resin is somewhat fragile for the little parts. I have broken some and fortunately repaired with a good cyano glue. I can recommend the brasin to the experienced modelers, but not to the beginners...