Now that we are approaching the end of the season (ish), thought I'd give a status report on the tires!
As a reminder, those tires come with 11/32nds of tread when new.
So far, we have put 6,500km (4000mi) on them since mid-November. Front and rears are currently all at 10/32nds, very even wear so far. We have maintained pressure to the door label (42 PSI) as good as possible (Ottawa really got a lot of temperature swings, almost 40C wide). Assuming we are willing to drive them to 5/32nds, I'd expect another 4-5 winters out of them, which would make us more than happy.
As for efficiency, I am still confident about what I said earlier. I think they are on par with what I get from the MXM4, accounting for the temperature difference. It's hard to have really comparable data between winter and summers cause of the temperature difference, but if I apply the same logic as before in my previous estimates, I am quite happy with them. I have an old set of X-Ice last year that had slightly less efficiency.
Road noise is not bad at all. I don't find them annoying in their tone or volume. I don't find them annoying at all.
Driving dynamics / winter performance is great. What I would expect from such tires. Never feared getting stuck, feels relatively sharp and all.
Overall, really happy with them. I'd highly recommend them if you need ones for next year!