Just to be a contrarian to most here it seems, I just wanted to say I really appreciate Ben's implementation of this (after discovering this thread last night and grabbing the Beta to play with it). It's actually something I really disliked in Illustrator, as it was always a choice between being able to replicate what I was doing or getting the exact curve I wanted, and rarely did the two ever meet. Being able to do that now without wrangling and praying is wonderful. So, thank you for that.
Though, to add a potentially silly question... Is there something that needs to be enabled to get the numbers on the red line as shown in the "Snapping2" video?
And the "construction mode" that the extended features of this became, I've seen that the mode should be activated by clicking a fifth icon in the tool snap labelled "Perform construction snapping", but this isn't present on my machine. Is there another element to activate it? (Windows 1.8.0.258)
Thank you greatly!