I haven't examined the Heller kit. I know of three others that have come and gone: Aurora (the first, in some oddball scale), Airfix (1/600, not bad but with a funny error in the shape of the main deck), and Lindbergh (forget it). Fujimi makes a respectable Graf Spee and Deutschland in 1/700.
The best German pocket battleship kits I've encountered are the ones from Italeri (sometimes distributed in Testor's boxes), in 1/720. They're among the nicest kits on 1/700 or 1/720 I've seen. The hulls are cast in an unusual pattern, with the underwater and above water portions held together by thin gates of plastic. (The modeler cuts away the gates. If you want a waterline model, throw the bottom part away; if you want to build it full-hull, a perfect fit between the halves is almost guaranteed.) Such things as the deck planking and the ports and hatches on the quarterdeck bulkheads are done with great subtlety. I did a Graf Spee with the Gold Medal Models photo-etched set; it was designed for the Fujimi kit, but works fine with the Italeri one.
I've always found it ironic that Nazi Germany and the Soviet Union, two of the most hideously represive regimes of modern history, produced some of the best-looking warships. The Graf Spee makes a particularly nice model in 1938 configuration, with the Spee coat of arms on each side of the bow, the gold eagle on the stern, and the red, white, and black "neutrality stripes" (for Mediterranean patrol duty during the Spanish Civil War) on the turrets. A couple of on-deck photos establish that the turrets had small individual coats of arms painted on their sides, but I haven't been able to figure out just what they looked like.
Raising the Graf Spee is a fascinating and exciting idea. Maybe, at the very least, we'll get some good underwater photos of the wreck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.