Inverted Dome
JE makes an inverted dome (essentially the same "D" shape), but again the dish is -39 cc's. I believe Diamonds are -36 cc's and have a .005 lower compression height on their stroker pistons (1.345" on Diamond vs 1.35 on JE). The stocker piston dish on both is very big in my opinion and leaves you with little choice other than a custom piston to get around 10 or 11:1 on most popular stroker combinations (4.3 & 4.5 stroke, 72 to 80 cc heads). The flat tops leave you around 12.5 or up.
Either will do custom dishes. In my opinion you can't go wrong with either of them. I know there are many custom pistons available, but I'm not aware of any other "D" dish off the shelf forged pistons, I'm sure if there are someone will chime in.
-TOM-