I've been wondering about this too. Just the other day when I was flying MSP-SEA (on an A333) I watched the Skyteam ad which claimed "priority seating" as one of the many benefits for SkyTeam Elites/Elite Plusses.

I know they claim that but I've noticed not all ST members treat each others' elite members as elite.

Since AM launched SEA-MEX, I've been pondering taking their flight to check it out, $960 is a bit steep for F, so I'd at least want to get a bulkhead or exit row for my 6'6" self.