The main concern I have heard about this kit is that the underwater hull is the wrong shape aft. You can see it compared to Trumpeter's hull here.
www.shipmodels.info/.../viewtopic.php
Another criticism has been the lack of mines, which Dragon supply in other kits.
I have the Z31 kit, which is unbuilt.
The 2cm A.A. guns are small and made up of fiddly parts. I assume they are the same as used on Dragon's Scharnhorst, which are overscale when completed. For me, they are not worth the effort required. I'd rather Dragon made simpler guns of the correct size or buy aftermarket ones in brass which are detailed and the correct size.
Although the forward bridge bulwarks are very detailed, the aft ones look crude by comparison imho. The forward bridge is the wrong shape for the Z31, but correct for Z39.
For me, the rivet detail on the funnel is overdone and needs to be removed, but YMMV.