The Overclock.net Mechanical Keyboard Guide has a good post depicting the difference between cylindrical vs. spherical key tops:
http://www.overclock.net/t/491752/mechanical-keyboard-guide#post_6009683The DCS profile offered in this current buy has a cylindrical top with different top slopes for each row, much like most modern keyboards. The DSA profile offered in the previous buy was a spherical top with no slope, so every key was the same shape regardless of row (larger keys being just an elongation of that shape). See http://keycapsdirect.com/key-caps.php for an illustration.