It is largely preference and comfort, but ultimately I think it should be about safety, complete retention of the weapon, and ease of access.
Let's face it...very few of us are as good as the Sons of Anarchy, so I doubt we'd be able to shoot effectively while riding (especially while the wife is on board!
).
I prefer carrying at around 4 or 4:30 on my hip, using a comfortable inside the waistband holster (IWB) with good retention properties. I carry outside on my belt (OWB) if it wasn't too hot to wear a vest or a jacket to keep the weapon concealed.
But there's another subject that you haven't brought up...where do you carry your additional rounds/magazine?
IMO, if you're going to carry, you need an additional mag or speedloader readily available at all times. Mine is on my left front hip in a belt holster, at around the 10 o'clock position.