Ok, so I did about 45k yesterday with around 500m of climbing and my first impressions are that these are going to amazing shoes for the type of riding I do.
In a size 43, the shoes came in at 195g each, so I save over 100g from my previous shoe, the S-Works 5.
They are also much roomier than the S-Works. Very generous toe box, but the heelcup is stiff and narrow so there is no slippage.
The insole feels very supportive for my average-arched feet. I was using a yellow Body Geometry insole in the S-Works, but I don't think that I'll need to move them to the Lakes.
If you're a sprinter, I don't think these would be the best shoes for you since the single Boa system makes it a little difficult to lock down the forefoot. But I don't race and don't do much sprinting, except for when I'm doing some intervals, so these will be fine for me.
Looking forward to seeing how these feel after 120+k ride.