What are the best ergonomic keyboards

Mass weight456.0 × 233.0 × 48.0 mm / 1,160 g 460.0 × 229.0 × 35.0 mm / 1,010 g 391.0 x 181.0 x 22.0 mm / 907 g 392.0 × 228.0 × 59.0 mm / 836 g488.0 × 263.0 mm × 61.0 mm / 1,020 g 503.0 × 262.0 × 83.0 mm / 1,300 g420.0 × 250.0 × 30.0 mm / 625 g518.0 × 274.0 × 68.0 mm / 1,440 g 453.0 x 213.0 x 33.0 mm / 807 g512.0 × 264.0 × 62.0 / 1,240 g 288.0 × 137.0 × 9 mm / 296 g520.0 × 272.0 × 68.0 mm / 1,400 g
Connection typeWireless, 2.4 GHz and BluetoothWireless, Blutooth 4.0 Wired USB 2.0Wireless, 2.4 GHz Wired, USB 2.0Wired USB 2.0Wireless, 2.4 GHzWireless, 2.4 GHz and BluetoothWireless, 2.4 GHzWired USB 2.0Wired USB 2.0Wired USB 2.0
Number of additional keys (extra keys / F keys with functions) / can be assigned individually20 / yes 16 / yes13 / yes 12 / yes 15 / yes28 + zoom slider / yes28 / yes7 / no15 / yes7 + trackball / noNone / no7 / no
Note ergonomicsVery goodGood to very goodGood to very goodVery goodGood to very goodVery goodWell Good to very goodGood to very goodGood to very goodWellRubber dome mechanism
Key switchRubber dome mechanism with chiclet buttonsRubber dome mechanism with chiclet buttonsRubber dome mechanismRubber dome mechanism with chiclet buttonsRubber dome mechanismRubber dome mechanismRubber dome mechanismRubber dome mechanismRubber dome mechanismRubber dome mechanismRubber dome mechanism with chiclet buttonsRubber dome mechanism
Height adjustment (front / rear)Yes NoNo noNo noYes NoNo noYes NoNo YesNo YesYes NoNo YesNo noNo Yes
Split key layout / split space barYes / YesYes / YesYes / YesYes / YesYes NoYes NoNo noYes / YesNo YesYes / YesYes / YesYes / Yes