Statblock illogicality of the day: Gargoyles don't need food, so the reason they eat fallen foes is to inflict pain. Eating corpses to inflict pain? 6 intelligence is showing through.

Apart from that and the weirdness of an [Earth] creature being able to fly, Gargoyles are surprisingly bland. They've got pretty good bonuses to all physical stats, the ability to wield weapons in addition to using two natural attacks. Their speed is good both on foot and in the air, and their DR is occasionally still relevant at lower levels.

Finally, there's Freeze: reasonably useful for springing ambushes at lower levels. Fortunately monsters don't tend to be as genre savvy as adventurers: a sole statue won't immediately arouse their suspicion.

In exchange for all this, gargoyles take a massive hit to intelligence and charisma, as well as 4 RHD (though being monstrous humanoid type, they're not that bad).

Accounting for all this, I think +0 LA is fitting here (somewhat considering +1). The same goes for kapoacinths, which are obviously slightly weaker.