I'm looking at booking a flight (PHL-LHR). The same flight is about $100 cheaper per person if bought through Finnair, with Finnair Flight Numbers. If I book through Finnair, I realize I'll only get 0.5 EQM's. However, will I still get the ability to choose MCE seats for free as an AA Platinum? Beyond having less EQM's, any other negatives of booking it through Finnair?