Took a chance on the zirconium build and the heft is perfect for my hand, 41 grams feels dense without being tiring. The thumb cutouts are machined smooth enough that I can flick it for hours without any hot spots.
The stainless steel build gives it a satisfying heft at 48g, and the 40 x 24 mm footprint fits perfectly between my fingers. I've been fidgeting with it all week and the machining feels precise, no rough edges anywhere.
The PEI version is so light I almost forgot it was in my pocket, but the zirconium's 41g heft gives it a satisfying thunk when I flick the slider. I've been fidgeting with it during zoom calls for a week now, and that 40mm width fits my thumb perfectly.