Depends on how's it done. The silent hero from the original Persona and every single Link in legend of Zelda suck hairy meatballs. If you want to make a silent hero, you have to make sure that you give him lots of choices to make in-game, so that you can actually feel like you're building a character. In Zelda games, there are no choices. There's just zelda, ganon, and the mute Link, who's supposed to be a hero... A hero that we know nothing about apart 'he's brave'. Stop. That, as I said, sucks.
The perfect silent hero is the one from Dragon Age Origins and subsequently, the old Kotor games. He was silent, but you had so many dialogue and story choices that you built a personality no problem, and you can actually feel yourself or the person you're creating living through the screen.
About 'ready-made' heroes, well, it depends on the writers. I've seen many build up heroes with messed up character developments.
My opinion? The perfect hero, the medium between the two, is Shepard from Mass Effect. He's not silent, but he's not already formed. The only thing you have about him is the voice and some key points in his past, but you can build everything from there. Personality, brutality, moral code... The perfect indication of this is that they make you choose his first name, but the last name still stays Shepard. I love that.