If you've got status locked for next year and missing out on the Aeroplan / AQM is not a big deal for you, I'd go with Aeroflot and save yourself the 5+ hours each way. Aeroflot J class is a fine product (and incidentally, Aeroflot domestic J class kills AC domestic J in every possible way). In-flight service on Aeroflot is very good. Where the airline struggles still is on the ground. If something goes wrong or you need to make changes, they are difficult to navigate even if you have Aeroflot status. So keep that in mind as well - if your plans change often at the last minute, then keep with AC and LH, whereby you have the Concierge in FRA who has saved me more than once between YYZ and Moscow.