They're not particularly stiff compared to carbon-soled shoes, but to me that makes them a great trail shoe. Construction seems solid and the placement of the middle d-ring over the middle of the foot provides a fit that doesn't pinch. The regular version fits narrow, so I ordered these. Size 12 dress shoe and the 47 fits perfect.
I upgraded to these pedals from my old m646's. Shaved more than a half-pound off my bike. I'm no weight-weenie, but it made an immediate difference. Still waiting for my Giro shoes to completely mate with them but so far, the cleat retention is great.
Does everything it claims--eliminates wind chill and breathes well. I ordered the XXL based on the chart (43-inch chest), though I normally wear a large or extra-large jersey. I like the fit; it's not skin-tight but it conforms to the body.