It feels like the keys are a little bit smaller than the K680, which is actually a benefit because the wrists remain still while using it whereas the 680 slightly wiggles. The wrists did not move at all throughout the first thirty minutes of work, despite what would appear. Without us-block, it appears to be an exact analog in all other respects. summary: Everyone who types frequently and dislikes pressing the keys should try it. By the conclusion of the workday, hands are still active, which fully accounts for the membrane's relative brittleness. And sure, there is Cyrillic, which surprised me. Delivered a day before delivery by calling, 4 days early.