I'm assuming OS X's FileVault is fine for full-disk encryption? It only sends your key to Apple if you choose to, and it's completely transparent from the end-user's perspective.
Personally I'd never trust any encryption provided by the OS - absolutely no one is in a better position to be compromised by bad guys (c.f. Recent Apple FBI scare).
Would rather use a third party solution that's not so easily coerced.
It's not about being competent enough to implement it properly. Microsoft's BitLocker is surely implemented just as competently. But because of their ubiquity, these are the most likely to have government-mandated backdoors in them that Apple/Microsoft employees are not allowed to tell you about because of gag orders.
