I was approached mid-January by a member from the ecobee team. The entire process took just over 3 weeks, and I agree with the other posters that it was one of the smoothest interview processes I've gone through. The stages included a behavioural/background phone screening, a followup call with a manager on the team, and a 2h technical interview that included a 90 minute pairing session on a personal project, and a 30 minute conversation with management. Every step along the way, every member of the team was lovely and accommodating to my time restraints. Easily one of the best processes I've experienced in my entire career. Like another candidate, I had also received an offer just prior to my third interview -- unfortunately I feel like they could have moved a bit faster, especially with a rejection, as I ended up having to make a very difficult decision with my other offer when I did not hear back by week's end.
Despite not getting an offer with ecobee, they did provide quite a bit of feedback which was a really nice touch.