I hope I'm wrong, but probably EIFS or Concrete panels. I'm pretty sure that's what they've used on the other ALT Hotels. On one hand though, the EIFS/concrete will give some diversity to EV which is mostly spandrel and glass at the moment.
I had to figure out the difference between EIFS and Concrete Pannels. Given the choice, which I wasn't, I'd take concrete panels. Without out knowing anything about the actual cost of those materials, there's just something that seems cheaper about EIFS. I went and looked up some of the other Hotel Alts based on your comments. The new one in Winnipeg looks quite nice. It has concrete pannelling, as does the one at Toronto Pearson. Both were mostly(I'll expand on that in a second), by the same architecture firm, LEYMICHAUD Archtecture & Design. They seems to have a fairly deep relationship with the Germain Group having done a number of their hotels including the Hotel Germain accross from the Calgary Tower (I love that one). I'd take a clone of the Winnipeg Alt especially.
That would mostly leave me feeling encouraged if it weren't for the afrorementioned mostly. It seems that LEYMICHAUD is teaming up with Avi for the EV Hotel Alt. Depsite loving Avi's work on their showhomes at Sunset Ridge in Cochrane, I'm not convinced of their experience doing high rises. That's cause for concern. Plus there is just something about that rendering that makes me think it's going to be EIFS. We shall see, I hope to be pleasantly surprised, but I'll remain cautious with my optimism.
Oh okay, concrete panels then. I would take those over EIFS also,. I also like Painted concrete (See Bravo/Ovation at Westbrooke are) I suppose in the end the colors will be a nice contrast to the silvery glass/spandrel of Evolution/First/Verve/The Hat/Arris/N3