Matias Alejandro is nice. I'm sort of neutral on
Matias, but it's a good, handsome name that will suit your son well throughout his life.
I hate
Christian /
Cristian, sorry. For one thing, I dislike the sound. Also, it's way too weighty and heavily associated with religion for me. What if he decides to convert to Judaism? What if he decides that he's an atheist? It's like naming a kid Jewish or Muslim to me. It comes across as flashing your (general you) religion in other people's faces. Sorry, but you asked for honest.