>>26442508Latios is typically more useful for getting kills and offensive pressure. Latias is mainly seen for filling gaps on teams defensively and/or for Healing Wish.
Latias is the more useful Mega because of the stat distribution favoring bulk and SpAtk, while Mega Latios is rarely seen since if anything, it's a Physical or Mixed Dragon Dancer.
Both generally run Life Orb with Hidden Power Fire for coverage, since if a Tyranitar catches them, they're usually dead anyhow.