If one was to my left and one to my right I would go for the one to my left. Being a right handed shooter I have a lot more "angle" to use comfortably with out straining to get on target or having to reposition my feet. Especially if I happen to be sitting or kneeling and could not stand up with out spooking the deer.

If it was just a matter of which way a deer was facing it would make no difference at all.