Originally Posted by Fat Superpowerdude
agreeing with Neliel Tu Oderschvank Latios has more special attack so it is generally the better specs user and scarf user. While Latias can still use it for a suprise factor it is still stopped by Jirachi can once the choice item has been revealed Latias is way more predictable. However Choice Scarf sets with Healing Wish are great to bring back another teammate in an offensive team.
I definitely do not recommend using the Specs set on Latias, but Healing Wish and OHKOing scarfed Genesect who normally comes in on Latias, is always nice. Her Scarf set is more of a surprise revenge killer/team supporter where as Latios is more of a wall breaker. Once Genesect is banned, if it is, Scarfed Latias will primarily be used for Healing Wish.