The Evo is thicker than the HD2, that's certain. In terms of the display, AMOLED displays are much more colorful but aren't necessarily any sharper than conventional displays. In general, they are a bit less sharp due to some color aliasing issues. That doesn't mean they stink but I've yet to see one as razor sharp as the best conventional TFT LCDs.
-------------------- Lisa Gade Editor in Chief, MobileTechReview