This first 777-300 is booked on one of the LHR-YYZ rotations for the time being (AC856/869).
As more 777s are delivered, they will spread throughout the AC network, and I hear LHR will get some of the 777-200LR familiarisation flights as well - before they take over from the A340-500s on the Asia work.
The new AC cabin seems very nice. It's a real shame I didn't get to experience it on my most recent AC trip back in Feb, as I think that would have made it an excellent flight (as almost every other aspect of the service was good).
You'll notice that even the Y cabin has mood lighting. Looks fairly similar to the system on the ANZ 772s.
Some of the 767s which will be sticking around for a bit will also be going through the refit process, and will have the same interiors fitted. The Air Canada
seatmap has an excellent amount of detail about facilities, location of power points in Y, and Y seat pitch. With five 767s already refitted, there will be a total of 23 767s upgraded with the "XM" interior (before the end of the year), and there will be two different configs depending on whether the aircraft was ex-AC (-333) or ex-CP (-375) pre-merger, as the locations of things like lavs and galleys vary slightly, and it was decided not to move these things in the refit.
(The AC web site says there are 4 different configs of unrefitted 767. I've travelled on at least two AC 767s which have different configs to the ones on the website, so thats 6 configs! I'm guessing these are the leased rather than owned aircraft.)
This will bring them on to the same level as the new 777s.
The XM 767s seem to crop up a fair bit at Heathrow, and the two ETOPS certified A319-LRs which fly the LHR-YYT flight are XM-ed.
Once sufficient 777s are delivered, they will displace A340s initially, and then the 330s.
Mike