I’ve been flying it for a while & have been in and out of Mexico City many times.
The trickiest bit of the 787 is getting it set up to go flying - once we start moving it all gets a lot easier.
It’s a very friendly aircraft that looks after me, with cabin air quality that’s in a different league to previous generations of Boeings. It has very few ‘gotchas’ and comes with more safety related kit and toys than anything else I’ve ever flown.
And as for flying out of MEX - I’d suggest that aircraft type should be the least of your worries…