What's the fastest weight-change mechanism?

Dial and twist-handle systems (Bowflex SelectTech, NordicTrack, and budget twist sets) are repeatedly described as the quickest—seconds per change. Selector-pin PowerBlocks take slightly longer (community estimates of 5–10 seconds), and screw/quick-lock styles like the Eisenlink take roughly 20 seconds per change, per owner reports, which is the tradeoff for their rattle-free, iron-like feel.