I'm going to be running Mixed Latios. This is the set I plan to use:
Latios @ ???
252 SpA / 252 Spe / 4 Atk
-Luster Purge / Psyshock / Psychic
I'm not sure which item would be better, though. Life Orb does make it pack a punch, but is the HP loss worth it? And if I use Latiosite, is the power worth the loss of a Mega slot? Any help would be appreciated!
As a normal Latios, even with the Life Orb, it's physical attacks won't do nearly as much as it would as a Mega Latios. So I say you use the Latiosite.
Hope I helped