I really love
Matteo, and it's definitely my favorite from the three. I hate
Mathias (though I like
Matthias, said mah-THIE-as, a lot).
Matheus looks very unattractive, though I'm not sure how it's pronounced. If it's MAT-ee-us or mah-THEE-us, it's rather ugly IMO.
My favorite is just
Matthew.